Fix aid keys

j3270/src/main/java/haus/nightmare/j3270/J3270App.java

@@ -48,7 +48,7 @@ public class J3270App extends JFrame implements ConnectionListener, ScreenUpdate
     public J3270App() {
         super("j3270 — Java TN3270 Terminal Emulator");
         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
-        setBackground(new Color(10, 10, 10));
+        setBackground(Color.BLACK);
 
         buildUI();
         buildMenuBar();
@@ -92,7 +92,7 @@ public class J3270App extends JFrame implements ConnectionListener, ScreenUpdate
         statusBar = new StatusBar();
 
         getContentPane().setLayout(new BorderLayout());
-        getContentPane().setBackground(new Color(10, 10, 10));
+        getContentPane().setBackground(Color.BLACK);
         getContentPane().add(terminalPanel, BorderLayout.CENTER);
         getContentPane().add(statusBar, BorderLayout.SOUTH);
     }

j3270/src/main/java/haus/nightmare/j3270/ui/TerminalPanel.java

@@ -123,7 +123,7 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
     public static final Color DEFAULT_MONO_PROTECTED_HIGH = new Color(255, 255, 255);
 
     // Default Background
-    public static final Color DEFAULT_BG_COLOR = new Color(10, 10, 10);
+    public static final Color DEFAULT_BG_COLOR = Color.BLACK;
 
     public TerminalPanel() {
         setupColors();
@@ -221,8 +221,8 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
                     int ox = getRenderOffsetX();
                     int oy = getRenderOffsetY();
                     ScreenBuffer sb = client.getScreenBuffer();
-                    int gridW = sb.getDisplayCols() * cellWidth;
-                    int gridH = sb.getDisplayRows() * cellHeight;
+                    int gridW = (sb != null ? sb.getDisplayCols() : 80) * cellWidth;
+                    int gridH = (sb != null ? sb.getDisplayRows() : 24) * cellHeight;
                     int gWidth = client.getGraphicsPlane().getCanvasWidth();
                     int gHeight = client.getGraphicsPlane().getCanvasHeight();
                     int px = (gridW > 0 && gWidth > 0) ? (int) Math.round((double) (e.getX() - ox) * gWidth / gridW) : (e.getX() - ox);
@@ -253,6 +253,7 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
 
                         if (isGraphic) {
                             clearSelection();
+                            sb.setCursorAddress(clickAddr);
                             int gridW = displayCols * cellWidth;
                             int gridH = displayRows * cellHeight;
                             int gWidth = client.getGraphicsPlane().getCanvasWidth();
@@ -995,11 +996,17 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
 
                 double curX = x;
                 double curY = y;
+                if (dir == GocaConstants.CD_TB) {
+                    curY += ch;
+                } else if (dir == GocaConstants.CD_RL) {
+                    curX -= cw;
+                }
+
                 for (int i = 0; i < text.length(); i++) {
                     String s = text.substring(i, i + 1);
                     int charW = fm.stringWidth(s);
                     int drawX = (int) Math.round(curX + Math.max(0, (cw - charW) / 2.0));
-                    int drawY = (int) Math.round(curY + ascent + Math.max(0, (ch - fm.getHeight()) / 2.0));
+                    int drawY = (int) Math.round(curY);
                     g2.drawString(s, drawX, drawY);
 
                     switch (dir) {

lib3270j/src/main/java/haus/nightmare/lib3270j/charset/EbcdicTranslator.java

@@ -81,6 +81,10 @@ public class EbcdicTranslator {
         return activeCodePage.isDBCS();
     }
 
+    public synchronized boolean isDBCS() {
+        return isDBCSCodePage();
+    }
+
     /**
      * Translate double-byte EBCDIC pair (b1, b2) to Unicode.
      */

lib3270j/src/main/java/haus/nightmare/lib3270j/datastream/DataStreamProcessor.java

@@ -1020,7 +1020,7 @@ public class DataStreamProcessor {
 
         switch (type) {
             case SF_RP_QUERY:
-                log.info("ReadPartition Query — sending all query replies");
+                log.info("ReadPartition Query — sending base query replies");
                 graphicsPlane.clear();
                 gocaDecoder.resetDefaults();
                 sendAllQueryReplies();
@@ -1029,7 +1029,9 @@ public class DataStreamProcessor {
                 if (fieldLen >= 6) {
                     int listType = data[offset + 5] & 0xFF;
                     log.info("ReadPartition QueryList type=" + String.format("0x%02x", listType));
-                    if (listType == SF_RPQ_ALL || listType == SF_RPQ_EQUIV) {
+                    if (listType == SF_RPQ_ALL) {
+                        sendCompleteQueryReplies();
+                    } else if (listType == SF_RPQ_EQUIV) {
                         sendAllQueryReplies();
                     } else if (listType == SF_RPQ_LIST) {
                         // Send only requested query replies
@@ -1071,7 +1073,22 @@ public class DataStreamProcessor {
             if ((i + 1) % 32 == 0)
                 sb.append("\n  ");
         }
-        log.warning(">>> SENDING Query Reply (" + qr.length + " bytes):\n  " + sb.toString().trim());
+        log.warning(">>> SENDING Base Query Reply (" + qr.length + " bytes):\n  " + sb.toString().trim());
+        if (outputSender != null) {
+            outputSender.send3270Data(qr);
+        }
+    }
+
+    private void sendCompleteQueryReplies() {
+        byte[] qr = qrBuilder.buildCompleteQueryReplies(screen.getMaxCols(), screen.getMaxRows(),
+                screen.getMaxCols() * screen.getMaxRows());
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < qr.length; i++) {
+            sb.append(String.format("%02x ", qr[i] & 0xFF));
+            if ((i + 1) % 32 == 0)
+                sb.append("\n  ");
+        }
+        log.warning(">>> SENDING Complete Query Reply (" + qr.length + " bytes):\n  " + sb.toString().trim());
         if (outputSender != null) {
             outputSender.send3270Data(qr);
         }

lib3270j/src/main/java/haus/nightmare/lib3270j/datastream/QueryReplyBuilder.java

@@ -15,16 +15,17 @@ public class QueryReplyBuilder {
 
     private static final Logger log = Logger.getLogger(QueryReplyBuilder.class.getName());
 
-    // Canned values from 3279-2 (matching sf.c)
     private static final int SW_3279_2 = 0x09;
     private static final int SH_3279_2 = 0x0c;
-    private static final int Xr_3279_2 = 0x000a02e5;
-    private static final int Yr_3279_2 = 0x0002006f;
+
+    // Usable Area physical dimensions matching IBM Host On-Demand DS3270.java (Inches, 96 dpi: 0x00010060)
+    private static final int Xr_HOD = 0x00010060;
+    private static final int Yr_HOD = 0x00010060;
 
     private final ScreenBuffer screen;
     private GraphicsMode graphicsMode = GraphicsMode.BOTH;
 
-    // Base query reply codes (text mode)
+    // Base query reply codes (text mode, matches HOD DS3270.java queryEquiv)
     private static final int[] SUPPORTED_QR_BASE = {
         QR_SUMMARY,      // 0x80 — summary must list itself
         QR_USABLE_AREA,  // 0x81
@@ -34,10 +35,11 @@ public class QueryReplyBuilder {
         QR_HIGHLIGHTING, // 0x87
         QR_REPLY_MODES,  // 0x88
         QR_DDM,          // 0x95 - Distributed Data Management (file transfer)
-        QR_IMP_PART,     // 0xa6
+        QR_AUXDA,        // 0x99 - Auxiliary Devices
+        QR_IMP_PART,     // 0xa6 - Implicit Partition Sizes
     };
 
-    // Vector graphics query reply codes matching HOD DS3270.java line 1723
+    // Vector graphics query reply codes matching HOD QueryReply3270Constants.java QR_3270_WITHOUT_DCBS_SUMMARY_STRING
     private static final int[] SUPPORTED_QR_VECTOR = {
         QR_SUMMARY,      // 0x80
         QR_USABLE_AREA,  // 0x81
@@ -46,17 +48,17 @@ public class QueryReplyBuilder {
         QR_COLOR,        // 0x86
         QR_HIGHLIGHTING, // 0x87
         QR_REPLY_MODES,  // 0x88
-        QR_SAVE_RESTORE, // 0x8c
+        QR_OUTLINING,    // 0x8c
         QR_DDM,          // 0x95
-        QR_TRANSPARENCY, // 0x99
+        QR_AUXDA,        // 0x99
         QR_IMP_PART,     // 0xa6
-        QR_RPQ_NAMES,    // 0xa8
-        QR_GRAPHICS,     // 0xb0
-        QR_GIMAGE,       // 0xb1
-        QR_AUX_DEV,      // 0xb2
-        QR_OEM_FMT,      // 0xb3
-        QR_GCOLOR,       // 0xb4
-        QR_GSYMBOLS,     // 0xb6
+        QR_TRANSPARENCY, // 0xa8
+        QR_SEGMENT,      // 0xb0
+        QR_PROCEDURE,    // 0xb1
+        QR_LINETYPE,     // 0xb2
+        QR_PORT,         // 0xb3
+        QR_GRCOLOR,      // 0xb4
+        QR_GRSYMBOLSET,  // 0xb6
     };
 
     public QueryReplyBuilder(ScreenBuffer screen) {
@@ -77,7 +79,8 @@ public class QueryReplyBuilder {
     }
 
     /**
-     * Build all query replies as a single AID_SF + structured field response.
+     * Build base query replies in response to a generic Read Partition Query (0x02).
+     * Returns base text/presentation summary structured fields (matches HOD DS3270.java line 1723).
      */
     public byte[] buildAllQueryReplies(int maxCols, int maxRows, int bufferSize) {
         ByteArrayOutputStream out = new ByteArrayOutputStream(512);
@@ -85,62 +88,90 @@ public class QueryReplyBuilder {
         // AID byte for structured field
         out.write(AID_SF);
 
-        // Summary
+        // Summary (0x80) - lists all supported capabilities
         appendQueryReply(out, QR_SUMMARY, buildSummary());
 
-        // Usable Area
+        // Usable Area (0x81)
         appendQueryReply(out, QR_USABLE_AREA, buildUsableArea(maxCols, maxRows, bufferSize));
 
-        // Alpha Partitions
+        // Alpha Partitions (0x84)
         appendQueryReply(out, QR_ALPHA_PART, buildAlphaPartitions(maxRows));
 
-        // Character Sets
+        // Character Sets (0x85)
         appendQueryReply(out, QR_CHARSETS, buildCharsets());
 
-        // Color
+        // Color (0x86)
         appendQueryReply(out, QR_COLOR, buildColor());
 
-        // Highlighting
+        // Highlighting (0x87)
         appendQueryReply(out, QR_HIGHLIGHTING, buildHighlighting());
 
         // Reply Modes (0x88)
         appendQueryReply(out, QR_REPLY_MODES, buildReplyModes());
 
-        if (graphicsMode.isVectorGraphicsEnabled()) {
-            // Save/Restore (0x8C)
-            appendQueryReply(out, QR_SAVE_RESTORE, buildSaveRestore());
+        boolean isDbcs = (screen != null && screen.getTranslator() != null && screen.getTranslator().isDBCS());
+        if (isDbcs) {
+            // Outlining (0x8C)
+            appendQueryReply(out, QR_OUTLINING, buildOutlining());
+            // DBCS Asia (0x91)
+            appendQueryReply(out, QR_DBCS_ASIA, buildDbcsAsia());
         }
 
         // Distributed Data Management (0x95)
         appendQueryReply(out, QR_DDM, buildDdm(4096));
 
-        if (graphicsMode.isVectorGraphicsEnabled()) {
-            // Transparency (0x99)
-            appendQueryReply(out, QR_TRANSPARENCY, buildTransparency());
-        }
+        // Auxiliary Devices (0x99)
+        appendQueryReply(out, QR_AUXDA, buildAuxDa());
 
         // Implicit Partition (0xA6)
         appendQueryReply(out, QR_IMP_PART, buildImplicitPartition(maxCols, maxRows));
 
-        // Vector Graphics QRs if enabled
+        log.info("Built " + out.size() + " bytes of base query replies (graphicsMode=" + graphicsMode + ")");
+        return out.toByteArray();
+    }
+
+    /**
+     * Build complete query replies including vector graphics (when SF_RPQ_ALL 0x80 is requested).
+     */
+    public byte[] buildCompleteQueryReplies(int maxCols, int maxRows, int bufferSize) {
+        ByteArrayOutputStream out = new ByteArrayOutputStream(512);
+        out.write(AID_SF);
+
+        appendQueryReply(out, QR_SUMMARY, buildSummary());
+        appendQueryReply(out, QR_USABLE_AREA, buildUsableArea(maxCols, maxRows, bufferSize));
+        appendQueryReply(out, QR_ALPHA_PART, buildAlphaPartitions(maxRows));
+        appendQueryReply(out, QR_CHARSETS, buildCharsets());
+        appendQueryReply(out, QR_COLOR, buildColor());
+        appendQueryReply(out, QR_HIGHLIGHTING, buildHighlighting());
+        appendQueryReply(out, QR_REPLY_MODES, buildReplyModes());
+
+        appendQueryReply(out, QR_OUTLINING, buildOutlining());
+        boolean isDbcs = (screen != null && screen.getTranslator() != null && screen.getTranslator().isDBCS());
+        if (isDbcs) {
+            appendQueryReply(out, QR_DBCS_ASIA, buildDbcsAsia());
+        }
+        appendQueryReply(out, QR_DDM, buildDdm(4096));
+        appendQueryReply(out, QR_AUXDA, buildAuxDa());
+        appendQueryReply(out, QR_IMP_PART, buildImplicitPartition(maxCols, maxRows));
+
         if (graphicsMode.isVectorGraphicsEnabled()) {
-            appendQueryReply(out, QR_RPQ_NAMES, buildRpqNames()); // 0xA8
-            appendQueryReply(out, QR_GRAPHICS, buildGraphics(maxCols, maxRows));   // 0xB0
-            appendQueryReply(out, QR_GIMAGE, buildGImage(maxCols, maxRows));       // 0xB1
-            appendQueryReply(out, QR_AUX_DEV, buildAuxDev());       // 0xB2
-            appendOemFmt(out);                                     // 0xB3
-            appendQueryReply(out, QR_GCOLOR, buildGColor());       // 0xB4
-            appendQueryReply(out, QR_GSYMBOLS, buildGSymbols());   // 0xB6
+            appendQueryReply(out, QR_TRANSPARENCY, buildTransparency()); // 0xA8
+            appendQueryReply(out, QR_SEGMENT, buildSegment(maxCols, maxRows));       // 0xB0
+            appendQueryReply(out, QR_PROCEDURE, buildProcedure(maxCols, maxRows));   // 0xB1
+            appendQueryReply(out, QR_LINETYPE, buildLineType());                     // 0xB2
+            appendPort(out);                                                         // 0xB3
+            appendQueryReply(out, QR_GRCOLOR, buildGrColor());                       // 0xB4
+            appendQueryReply(out, QR_GRSYMBOLSET, buildGrSymbolSet());               // 0xB6
         }
 
-        log.info("Built " + out.size() + " bytes of all query replies (graphicsMode=" + graphicsMode + ")");
+        log.info("Built " + out.size() + " bytes of complete query replies (graphicsMode=" + graphicsMode + ")");
         return out.toByteArray();
     }
 
     /**
      * Build specific query replies in response to a Read Partition Query List (SF_RPQ_LIST).
      * For any unsupported requested query code, emits a QR_NULL (0xFF) structured field
-     * matching x3270 sf.c behavior.
+     * matching HOD DS3270.java line 1835.
      */
     public byte[] buildQueryReplies(byte[] requestedCodes, int maxCols, int maxRows, int bufferSize) {
         if (requestedCodes == null || requestedCodes.length == 0) {
@@ -174,72 +205,70 @@ public class QueryReplyBuilder {
                 case QR_REPLY_MODES:
                     appendQueryReply(out, QR_REPLY_MODES, buildReplyModes());
                     break;
-                case QR_SAVE_RESTORE:
-                    if (graphicsMode.isVectorGraphicsEnabled()) {
-                        appendQueryReply(out, QR_SAVE_RESTORE, buildSaveRestore());
+                case QR_OUTLINING: // 0x8C
+                    appendQueryReply(out, QR_OUTLINING, buildOutlining());
+                    break;
+                case QR_DBCS_ASIA: // 0x91
+                    if (screen != null && screen.getTranslator() != null && screen.getTranslator().isDBCS()) {
+                        appendQueryReply(out, QR_DBCS_ASIA, buildDbcsAsia());
                     } else {
                         appendQueryReply(out, QR_NULL, new byte[0]);
                     }
                     break;
-                case QR_DDM:
+                case QR_DDM: // 0x95
                     appendQueryReply(out, QR_DDM, buildDdm(4096));
                     break;
-                case QR_TRANSPARENCY:
+                case QR_AUXDA: // 0x99
+                    appendQueryReply(out, QR_AUXDA, buildAuxDa());
+                    break;
+                case QR_IMP_PART: // 0xA6
+                    appendQueryReply(out, QR_IMP_PART, buildImplicitPartition(maxCols, maxRows));
+                    break;
+                case QR_TRANSPARENCY: // 0xA8
                     if (graphicsMode.isVectorGraphicsEnabled()) {
                         appendQueryReply(out, QR_TRANSPARENCY, buildTransparency());
                     } else {
                         appendQueryReply(out, QR_NULL, new byte[0]);
                     }
                     break;
-                case QR_IMP_PART:
-                    appendQueryReply(out, QR_IMP_PART, buildImplicitPartition(maxCols, maxRows));
-                    break;
-                case QR_RPQ_NAMES:
-                case QR_RPQNAMES:
+                case QR_SEGMENT: // 0xB0
                     if (graphicsMode.isVectorGraphicsEnabled()) {
-                        appendQueryReply(out, code, buildRpqNames());
+                        appendQueryReply(out, QR_SEGMENT, buildSegment(maxCols, maxRows));
                     } else {
                         appendQueryReply(out, QR_NULL, new byte[0]);
                     }
                     break;
-                case QR_GRAPHICS:
+                case QR_PROCEDURE: // 0xB1
                     if (graphicsMode.isVectorGraphicsEnabled()) {
-                        appendQueryReply(out, QR_GRAPHICS, buildGraphics(maxCols, maxRows));
+                        appendQueryReply(out, QR_PROCEDURE, buildProcedure(maxCols, maxRows));
                     } else {
                         appendQueryReply(out, QR_NULL, new byte[0]);
                     }
                     break;
-                case QR_GIMAGE:
+                case QR_LINETYPE: // 0xB2
                     if (graphicsMode.isVectorGraphicsEnabled()) {
-                        appendQueryReply(out, QR_GIMAGE, buildGImage(maxCols, maxRows));
+                        appendQueryReply(out, QR_LINETYPE, buildLineType());
                     } else {
                         appendQueryReply(out, QR_NULL, new byte[0]);
                     }
                     break;
-                case QR_AUX_DEV:
+                case QR_PORT: // 0xB3
                     if (graphicsMode.isVectorGraphicsEnabled()) {
-                        appendQueryReply(out, QR_AUX_DEV, buildAuxDev());
+                        appendPort(out);
                     } else {
                         appendQueryReply(out, QR_NULL, new byte[0]);
                     }
                     break;
-                case QR_OEM_FMT:
+                case QR_GRCOLOR: // 0xB4
                     if (graphicsMode.isVectorGraphicsEnabled()) {
-                        appendOemFmt(out);
+                        appendQueryReply(out, QR_GRCOLOR, buildGrColor());
                     } else {
                         appendQueryReply(out, QR_NULL, new byte[0]);
                     }
                     break;
-                case QR_GCOLOR:
+                case QR_GRSYMBOLSET: // 0xB6
                     if (graphicsMode.isVectorGraphicsEnabled()) {
-                        appendQueryReply(out, QR_GCOLOR, buildGColor());
-                    } else {
-                        appendQueryReply(out, QR_NULL, new byte[0]);
-                    }
-                    break;
-                case QR_GSYMBOLS:
-                    if (graphicsMode.isVectorGraphicsEnabled()) {
-                        appendQueryReply(out, QR_GSYMBOLS, buildGSymbols());
+                        appendQueryReply(out, QR_GRSYMBOLSET, buildGrSymbolSet());
                     } else {
                         appendQueryReply(out, QR_NULL, new byte[0]);
                     }
@@ -268,31 +297,35 @@ public class QueryReplyBuilder {
     private byte[] buildSummary() {
         ByteArrayOutputStream out = new ByteArrayOutputStream();
         int[] codes = graphicsMode.isVectorGraphicsEnabled() ? SUPPORTED_QR_VECTOR : SUPPORTED_QR_BASE;
+        boolean isDbcs = (screen != null && screen.getTranslator() != null && screen.getTranslator().isDBCS());
         for (int code : codes) {
             out.write(code);
+            if (isDbcs && code == QR_OUTLINING) {
+                out.write(QR_DBCS_ASIA); // 0x91
+            }
         }
         return out.toByteArray();
     }
 
     private byte[] buildUsableArea(int maxCols, int maxRows, int bufferSize) {
         ByteArrayOutputStream out = new ByteArrayOutputStream(19);
-        out.write(0x01);                     // 12/14-bit addressing
+        out.write(graphicsMode.isVectorGraphicsEnabled() ? 0x03 : 0x01); // 12/14-bit addressing + graphics flag (matching HOD DS3270.java)
         out.write(0x00);                     // no special character features
         out.write((maxCols >> 8) & 0xFF);    // usable width high
         out.write(maxCols & 0xFF);           // usable width low
         out.write((maxRows >> 8) & 0xFF);    // usable height high
         out.write(maxRows & 0xFF);           // usable height low
-        out.write(0x01);                     // units (mm)
-        // Xr (4 bytes) - canned from 3279-2
-        out.write((Xr_3279_2 >> 24) & 0xFF);
-        out.write((Xr_3279_2 >> 16) & 0xFF);
-        out.write((Xr_3279_2 >> 8) & 0xFF);
-        out.write(Xr_3279_2 & 0xFF);
-        // Yr (4 bytes) - canned from 3279-2
-        out.write((Yr_3279_2 >> 24) & 0xFF);
-        out.write((Yr_3279_2 >> 16) & 0xFF);
-        out.write((Yr_3279_2 >> 8) & 0xFF);
-        out.write(Yr_3279_2 & 0xFF);
+        out.write(0x00);                     // units (0x00 = inches, matching IBM Host On-Demand QR_USEAREA_STRING)
+        // Xr (4 bytes) - matching IBM Host On-Demand QR_USEAREA_STRING
+        out.write((Xr_HOD >> 24) & 0xFF);
+        out.write((Xr_HOD >> 16) & 0xFF);
+        out.write((Xr_HOD >> 8) & 0xFF);
+        out.write(Xr_HOD & 0xFF);
+        // Yr (4 bytes) - matching IBM Host On-Demand QR_USEAREA_STRING
+        out.write((Yr_HOD >> 24) & 0xFF);
+        out.write((Yr_HOD >> 16) & 0xFF);
+        out.write((Yr_HOD >> 8) & 0xFF);
+        out.write(Yr_HOD & 0xFF);
         int charW = getCharWidth();
         int charH = getCharHeight();
         out.write(charW);                    // AW
@@ -304,6 +337,9 @@ public class QueryReplyBuilder {
     }
 
     public int getCharWidth() {
+        if (screen != null && screen.getTranslator() != null && screen.getTranslator().isDBCS()) {
+            return 12;
+        }
         return SW_3279_2; // 9
     }
 
@@ -344,8 +380,8 @@ public class QueryReplyBuilder {
             cpgid = screen.getTranslator().getCpgid();
         }
 
-        if (graphicsMode.isProgrammedSymbolsEnabled()) {
-            // Programmed Symbols mode (3279 PS with LoadPS 0x0A, flags1 = 0xA2 for GE + PS + CGCSGID)
+        if (graphicsMode == GraphicsMode.PROGRAMMED_SYMBOLS) {
+            // Programmed Symbols only mode (3279 PS with LoadPS 0x0A, flags1 = 0xA2 for GE + PS + CGCSGID)
             ByteArrayOutputStream out = new ByteArrayOutputStream(65);
             out.write(0xa2); // flags: GE (0x80), PS/Loadable Charsets (0x20), CGCSGID present (0x02)
             out.write(0x00); // more flags
@@ -458,7 +494,28 @@ public class QueryReplyBuilder {
         return out.toByteArray();
     }
 
-    private byte[] buildGraphics(int maxCols, int maxRows) {
+    public byte[] buildOutlining() {
+        // HOD QueryReply3270Constants.java QR_OUTLINING_STRING ("\u0000\n\u0081\u008c\u0000\u0000\u0000\u0000\u0000\u0000")
+        return new byte[]{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+    }
+
+    public byte[] buildDbcsAsia() {
+        // HOD QueryReply3270Constants.java QR_DBCS_ASIA_STRING ("\u0000\u000b\u0081\u0091\u0000\u0003\u0001\u0080\u0003\u0002\u0001")
+        return new byte[]{ 0x00, 0x03, 0x01, (byte) 0x80, 0x03, 0x02, 0x01 };
+    }
+
+    public byte[] buildAuxDa() {
+        // HOD QueryReply3270Constants.java QR_AUXDA_STRING ("\u0000\u0006\u0081\u0099\u0000\u0000")
+        return new byte[]{ 0x00, 0x00 };
+    }
+
+    public byte[] buildTransparency() {
+        // HOD QueryReply3270Constants.java QR_TRANSPARENCY_STRING ("\u0000\t\u0081\u00a8\u0002\u0000\u00f0\u00ff\u00ff")
+        return new byte[]{ 0x02, 0x00, (byte) 0xF0, (byte) 0xFF, (byte) 0xFF };
+    }
+
+    public byte[] buildSegment(int maxCols, int maxRows) {
+        // HOD QueryReply3270Constants.java QR_SEGMENT_STRING ("\u0000\u000b\u0081\u00b0\u0080\u0002\u0000\u0000\u0000\u00fc\u0000")
         return new byte[]{
             (byte) 0x80, 0x02,
             0x00, 0x00,
@@ -467,7 +524,12 @@ public class QueryReplyBuilder {
         };
     }
 
-    private byte[] buildGImage(int maxCols, int maxRows) {
+    public byte[] buildGraphics(int maxCols, int maxRows) {
+        return buildSegment(maxCols, maxRows);
+    }
+
+    public byte[] buildProcedure(int maxCols, int maxRows) {
+        // HOD QueryReply3270Constants.java QR_PROCEDURE_STRING ("\u0000\u0015\u0081\u00b1\u0000\u0001\u0000\u0000\u0000\u00fc\u0000\u0006@\u0006@\u0006\u0001\u00ff\u00ff\u00ff\u00f0")
         return new byte[]{
             0x00, 0x01,
             0x00, 0x00,
@@ -478,11 +540,12 @@ public class QueryReplyBuilder {
         };
     }
 
-    public byte[] buildAuxDevice() {
-        return buildAuxDev();
+    public byte[] buildGImage(int maxCols, int maxRows) {
+        return buildProcedure(maxCols, maxRows);
     }
 
-    private byte[] buildAuxDev() {
+    public byte[] buildLineType() {
+        // HOD QueryReply3270Constants.java QR_LINETYPE_STRING ("\u0000\u0018\u0081\u00b2\u0000\t\u0000\u0007\u0001\u0001\u0002\u0002\u0003\u0003\u0004\u0004\u0005\u0005\u0006\u0006\u0007\u0007\b\b")
         return new byte[]{
             0x00, 0x09, 0x00, 0x07,
             0x01, 0x01, 0x02, 0x02, 0x03, 0x03, 0x04, 0x04,
@@ -490,38 +553,36 @@ public class QueryReplyBuilder {
         };
     }
 
-    private byte[] buildSaveRestore() {
-        // HOD DS3270.java line 1768: 6 bytes payload
-        return new byte[]{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+    public byte[] buildAuxDev() {
+        return buildLineType();
     }
 
-    private byte[] buildTransparency() {
-        // HOD DS3270.java line 1782: 2 bytes payload
-        return new byte[]{ 0x00, 0x00 };
+    public byte[] buildAuxDevice() {
+        return buildLineType();
     }
 
-    private byte[] buildRpqNames() {
-        // HOD DS3270.java line 1798: 5 bytes payload
-        return new byte[]{ 0x02, 0x00, (byte) 0xF0, (byte) 0xFF, (byte) 0xFF };
-    }
-
-    private void appendOemFmt(ByteArrayOutputStream out) {
-        // HOD DS3270.java line 1814: 4 distinct OEM format sub-fields
-        appendQueryReply(out, QR_OEM_FMT, new byte[]{
+    public void appendPort(ByteArrayOutputStream out) {
+        // HOD QueryReply3270Constants.java QR_PORT_STRING (4 OEM format sub-fields, 64 bytes total)
+        appendQueryReply(out, QR_PORT, new byte[]{
             0x00, 0x03, 0x02, (byte) 0x90, 0x09, 0x01, 0x00, 0x03, 0x02, (byte) 0x80, 0x00, 0x7F, (byte) 0xFF
         });
-        appendQueryReply(out, QR_OEM_FMT, new byte[]{
+        appendQueryReply(out, QR_PORT, new byte[]{
             0x00, 0x04, 0x08, 0x40, 0x07, 0x03, 0x00, 0x03, (byte) 0x80, 0x00, 0x02
         });
-        appendQueryReply(out, QR_OEM_FMT, new byte[]{
+        appendQueryReply(out, QR_PORT, new byte[]{
             0x00, 0x05, 0x02, (byte) 0x80, 0x09, 0x01, 0x00, 0x01, 0x02, (byte) 0x80, 0x00, 0x7F, (byte) 0xFF
         });
-        appendQueryReply(out, QR_OEM_FMT, new byte[]{
+        appendQueryReply(out, QR_PORT, new byte[]{
             0x00, 0x07, 0x08, 0x40, 0x07, 0x03, 0x00, 0x01, 0x00, 0x00, 0x1C
         });
     }
 
-    private byte[] buildGColor() {
+    public void appendOemFmt(ByteArrayOutputStream out) {
+        appendPort(out);
+    }
+
+    public byte[] buildGrColor() {
+        // HOD QueryReply3270Constants.java QR_GRCOLOR_STRING (109 bytes total)
         ByteArrayOutputStream out = new ByteArrayOutputStream(110);
         out.write(0x00); out.write(0x04); out.write(0x00); out.write(0xFF); out.write(0xFF);
         out.write(0x00); out.write(0x10); out.write(0x00); out.write(0x10);
@@ -541,11 +602,35 @@ public class QueryReplyBuilder {
         return out.toByteArray();
     }
 
-    private byte[] buildGSymbols() {
+    public byte[] buildGColor() {
+        return buildGrColor();
+    }
+
+    public byte[] buildGrSymbolSet() {
+        int charW = getCharWidth();
+        int charH = getCharHeight();
+        int cgcsgid = 0x02B9;
+        int cpgid = 0x0025;
+        if (screen != null && screen.getTranslator() != null) {
+            cgcsgid = screen.getTranslator().getCgcsgid();
+            cpgid = screen.getTranslator().getCpgid();
+        }
         return new byte[]{
-            0x00, 0x00, 0x0C, 0x18, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x12,
-            0x01, 0x00, 0x00, (byte) 0xF0, (byte) 0xC1, (byte) 0xC1, 0x00, 0x00,
-            0x0C, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+            0x00, 0x00, (byte) charW, (byte) charH, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x12,
+            0x01, 0x00, 0x00, (byte) 0xF0, (byte) ((cgcsgid >> 8) & 0xFF), (byte) (cgcsgid & 0xFF), 0x00, 0x00,
+            (byte) charW, (byte) charH, 0x00, 0x00, (byte) 0xF0, (byte) ((cgcsgid >> 8) & 0xFF), (byte) (cgcsgid & 0xFF), 0x00, 0x00
         };
     }
+
+    public byte[] buildGSymbols() {
+        return buildGrSymbolSet();
+    }
+
+    public byte[] buildSaveRestore() {
+        return buildOutlining();
+    }
+
+    public byte[] buildRpqNames() {
+        return buildTransparency();
+    }
 }

lib3270j/src/main/java/haus/nightmare/lib3270j/graphics/GocaConstants.java

@@ -60,10 +60,9 @@ public final class GocaConstants {
     public static final int G_GSCR      = 0x35; // Set Character Shear
     public static final int G_GSMCEL    = 0x37; // Set Marker Cell
     public static final int G_GSCS      = 0x38; // Set Character Set
-    public static final int G_GSMP      = 0x39; // Set Marker Precision
-    public static final int G_GSETAG    = 0x39; // Set Pick Identifier / Tag
+    public static final int G_GSCC      = 0x39; // Set Character Precision
     public static final int G_GSCD      = 0x3A; // Set Character Direction
-    public static final int G_GSCC      = 0x3B; // Set Character Precision
+    public static final int G_GSMP      = 0x3B; // Set Marker Precision
     public static final int G_GSMS_SET  = 0x3C; // Set Marker Set
     public static final int G_ENDPROLOGUE = 0x3E; // End Prologue
     public static final int G_GPOP      = 0x3F; // Pop Attribute

lib3270j/src/main/java/haus/nightmare/lib3270j/graphics/GocaDecoder.java

@@ -27,6 +27,7 @@ public class GocaDecoder {
     private int markerType = GocaConstants.MK_PLUS;
     private int markerSize = 5;
     private int markerColor = GocaConstants.GOCA_COLORS[0];
+    private int markerPrecision = 0;
     private int pattern = GocaConstants.PT_SOLID;
     private int patternSet = 0;
     private int fillColor = GocaConstants.GOCA_COLORS[0];
@@ -62,9 +63,6 @@ public class GocaDecoder {
 
     // Segment Store for retained graphics / segment calling (G_GCALL 0x2A)
     private final java.util.Map<Integer, byte[]> segmentStore = new java.util.HashMap<>();
-    private final java.util.Map<Integer, Integer> segmentChainMap = new java.util.HashMap<>();
-    private final java.util.List<Integer> segmentOrderList = new java.util.ArrayList<>();
-    private final java.util.Set<Integer> chainedTargets = new java.util.HashSet<>();
     private int callDepth = 0;
 
     /**
@@ -148,6 +146,8 @@ public class GocaDecoder {
         return graphicCursorY;
     }
 
+    public static final int GDDM_CURSOR_OFFSET_Y = 0;
+
     public synchronized void setGraphicCursorPosition(int x, int y) {
         this.graphicCursorX = x;
         this.graphicCursorY = y;
@@ -205,9 +205,6 @@ public class GocaDecoder {
         graphicCursorX = 0;
         graphicCursorY = 0;
         segmentStore.clear();
-        segmentChainMap.clear();
-        segmentOrderList.clear();
-        chainedTargets.clear();
         segmentBoundsMap.clear();
         activeSegmentsInOrder.clear();
         currentSegId = 0;
@@ -223,6 +220,7 @@ public class GocaDecoder {
         markerType = GocaConstants.MK_PLUS;
         markerSize = 5;
         markerColor = curColor;
+        markerPrecision = 0;
         pattern = GocaConstants.PT_SOLID;
         patternSet = 0;
         fillColor = curColor;
@@ -279,7 +277,7 @@ public class GocaDecoder {
         // Flexible 1-byte attribute orders (support both short 2-byte or long 3-byte if len byte == 1)
         if (order == GocaConstants.G_GSPT || order == GocaConstants.G_GSMT ||
             order == GocaConstants.G_GSCS || order == GocaConstants.G_GSCD ||
-            order == GocaConstants.G_GSCC ||
+            order == GocaConstants.G_GSCC || order == GocaConstants.G_GSMP ||
             order == GocaConstants.G_GSMS_SET || order == GocaConstants.G_GBAR) {
             return (data[idx + 1] == 0x01 && idx + 2 < end) ? 3 : 2;
         }
@@ -290,61 +288,6 @@ public class GocaDecoder {
         return (data[idx + 1] & 0xFF) + 2;
     }
 
-    private void indexSegments(byte[] data, int offset, int length) {
-        int idx = offset;
-        int end = offset + length;
-        while (idx < end) {
-            int order = data[idx] & 0xFF;
-            if (order == GocaConstants.G_BEGSEGM) {
-                int segStart = idx;
-                int segLen = getOrderLength(data, idx, end);
-                if (segLen <= 0 || idx + 5 >= end) {
-                    break;
-                }
-                int segId = ((data[idx + 2] & 0xFF) << 24) |
-                            ((data[idx + 3] & 0xFF) << 16) |
-                            ((data[idx + 4] & 0xFF) << 8)  |
-                            (data[idx + 5] & 0xFF);
-
-                int nextId = 0;
-                if (segLen >= 14 && (data[idx + 1] & 0xFF) >= 12) {
-                    nextId = ((data[idx + 10] & 0xFF) << 24) |
-                             ((data[idx + 11] & 0xFF) << 16) |
-                             ((data[idx + 12] & 0xFF) << 8)  |
-                             (data[idx + 13] & 0xFF);
-                }
-
-                int searchIdx = idx + segLen;
-                while (searchIdx < end) {
-                    int o = data[searchIdx] & 0xFF;
-                    int oLen = getOrderLength(data, searchIdx, end);
-                    if (oLen <= 0) break;
-                    if (o == GocaConstants.G_ENDSEGM) {
-                        searchIdx += oLen;
-                        break;
-                    }
-                    searchIdx += oLen;
-                }
-                int fullSegLen = searchIdx - segStart;
-                if (fullSegLen > 0 && segStart + fullSegLen <= end) {
-                    byte[] segBytes = new byte[fullSegLen];
-                    System.arraycopy(data, segStart, segBytes, 0, fullSegLen);
-                    segmentStore.put(segId, segBytes);
-                    segmentOrderList.add(segId);
-                    if (nextId != 0) {
-                        segmentChainMap.put(segId, nextId);
-                        chainedTargets.add(nextId);
-                    }
-                }
-                idx = searchIdx;
-            } else {
-                int oLen = getOrderLength(data, idx, end);
-                if (oLen <= 0) break;
-                idx += oLen;
-            }
-        }
-    }
-
     /**
      * Decodes a stream of GOCA drawing orders (matching IBM Host On-Demand HODDecoder.decodeGOCA).
      */
@@ -382,7 +325,7 @@ public class GocaDecoder {
     }
 
     /**
-     * Executes a stored procedure segment by segment ID, traversing chained next segments.
+     * Executes a stored procedure segment by segment ID.
      */
     public synchronized void procedureSegment(int segId) {
         if (segId == 0) return;
@@ -397,12 +340,6 @@ public class GocaDecoder {
             decodeStreamDirect(segData, 0, segData.length);
             callDepth--;
             currentSegId = savedSeg;
-
-            // Execute chained segments
-            Integer nextId = segmentChainMap.get(segId);
-            if (nextId != null && nextId != 0 && callDepth < 16) {
-                procedureSegment(nextId);
-            }
         } else {
             logger.warning("procedureSegment: Segment not found in store: " + segId);
         }
@@ -440,10 +377,6 @@ public class GocaDecoder {
             end = offset + length;
         }
 
-        if (callDepth == 0) {
-            indexSegments(inputData, idx, end - idx);
-        }
-
         decodeStreamDirect(inputData, idx, end - idx);
     }
 
@@ -491,6 +424,27 @@ public class GocaDecoder {
                         SegmentBounds sb = segmentBoundsMap.computeIfAbsent(segId, SegmentBounds::new);
                         activeSegmentsInOrder.remove(sb);
                         activeSegmentsInOrder.add(sb);
+
+                        if (segId != 0 && callDepth == 0) {
+                            int segStart = idx;
+                            int searchIdx = idx + orderLen;
+                            while (searchIdx < end) {
+                                int o = inputData[searchIdx] & 0xFF;
+                                int oLen = getOrderLength(inputData, searchIdx, end);
+                                if (oLen <= 0) break;
+                                if (o == GocaConstants.G_ENDSEGM) {
+                                    searchIdx += oLen;
+                                    break;
+                                }
+                                searchIdx += oLen;
+                            }
+                            int fullSegLen = searchIdx - segStart;
+                            if (fullSegLen > 0 && segStart + fullSegLen <= end) {
+                                byte[] segBytes = new byte[fullSegLen];
+                                System.arraycopy(inputData, segStart, segBytes, 0, fullSegLen);
+                                segmentStore.put(segId, segBytes);
+                            }
+                        }
                     }
                     if (idx + 6 < end) flag0 = inputData[idx + 6] & 0xFF;
                     if (idx + 7 < end) flag1 = inputData[idx + 7] & 0xFF;
@@ -503,7 +457,6 @@ public class GocaDecoder {
                 }
                 case GocaConstants.G_ENDSEGM: { // End Segment (0x71)
                     logger.info(String.format("GOCA ENDSEGM: segId=%d", currentSegId));
-                    int finishedSegId = currentSegId;
                     if (currentSegId != 0) {
                         SegmentBounds sb = segmentBoundsMap.get(currentSegId);
                         if (sb != null) {
@@ -515,36 +468,9 @@ public class GocaDecoder {
                     }
                     currentSegId = 0;
                     idx += orderLen;
-                    if (finishedSegId != 0 && callDepth < 16) {
-                        Integer nextId = segmentChainMap.get(finishedSegId);
-                        if (nextId != null && nextId != 0) {
-                            byte[] nextSeg = segmentStore.get(nextId);
-                            if (nextSeg != null) {
-                                logger.info("Executing chained segment nextId=" + nextId);
-                                currentSegId = nextId;
-                                SegmentBounds targetSb = segmentBoundsMap.computeIfAbsent(nextId, SegmentBounds::new);
-                                activeSegmentsInOrder.remove(targetSb);
-                                activeSegmentsInOrder.add(targetSb);
-                                callDepth++;
-                                decodeStreamDirect(nextSeg, 0, nextSeg.length);
-                                callDepth--;
-                                currentSegId = 0;
-                            }
-                        }
-                    }
-                    break;
-                }
-                case GocaConstants.G_GSETAG: { // Set Pick Identifier / Tag (0x39)
-                    if (currentSegId != 0 && payloadLen >= 2 && idx + 3 < end) {
-                        int tag = ((inputData[idx + 2] & 0xFF) << 8) | (inputData[idx + 3] & 0xFF);
-                        SegmentBounds sb = segmentBoundsMap.get(currentSegId);
-                        if (sb != null) {
-                            sb.tag = tag;
-                        }
-                    }
-                    idx += orderLen;
                     break;
                 }
+
                 case GocaConstants.G_ENDPROLOGUE: { // End Prologue (0x3E)
                     idx += orderLen;
                     break;
@@ -704,16 +630,22 @@ public class GocaDecoder {
                     break;
                 }
                 case GocaConstants.G_GSCS: { // Set Character Set (0x38)
-                    charSet = (orderLen == 3) ? (inputData[idx + 2] & 0xFF) : (inputData[idx + 1] & 0xFF);
+                    int cs = (orderLen == 3) ? (inputData[idx + 2] & 0xFF) : (inputData[idx + 1] & 0xFF);
+                    charSet = (cs == 0xF0) ? 0 : cs;
                     idx += orderLen;
                     break;
                 }
-                case GocaConstants.G_GSCC: { // Set Character Precision (0x3B)
+                case GocaConstants.G_GSCC: { // Set Character Precision (0x39)
                     charPrecision = (orderLen == 3) ? (inputData[idx + 2] & 0xFF) : (inputData[idx + 1] & 0xFF);
                     if (charPrecision == 0) charPrecision = GocaConstants.CP_STRING;
                     idx += orderLen;
                     break;
                 }
+                case GocaConstants.G_GSMP: { // Set Marker Precision (0x3B)
+                    markerPrecision = (orderLen == 3) ? (inputData[idx + 2] & 0xFF) : (inputData[idx + 1] & 0xFF);
+                    idx += orderLen;
+                    break;
+                }
                 case GocaConstants.G_GSMX:
                 case GocaConstants.G_GSMS_SET:
                 case GocaConstants.G_GPOP: {
@@ -901,8 +833,6 @@ public class GocaDecoder {
                     activeSegmentsInOrder.clear();
                     segmentBoundsMap.clear();
                     segmentStore.clear();
-                    segmentOrderList.clear();
-                    chainedTargets.clear();
                     logger.info("GOCA P_ERASE: erased graphics presentation space and cleared segment stores");
                     idx += 2;
                     break;
@@ -925,11 +855,7 @@ public class GocaDecoder {
                     }
                     break;
                 }
-                case GocaConstants.P_SETCUR: { // 0x31: Set Graphic Cursor Position
-                    if (idx + 5 <= end) {
-                        this.graphicCursorX = readCoord(data, idx + 2);
-                        this.graphicCursorY = readCoord(data, idx + 4);
-                    }
+                case GocaConstants.P_SETCUR: { // 0x31: Set Graphic Cursor Position (HODGraphicCursorPosition - No-op per HOD architecture)
                     if (idx + 1 < end) {
                         int len = data[idx + 1] & 0xFF;
                         idx += 2 + len;
@@ -1372,24 +1298,49 @@ public class GocaDecoder {
         double cw = charWidth > 0 ? ((double) charWidth * plane.getCanvasWidth() / (plane.getScreenCols() * 9.0)) : 10.0;
         double ch = charHeight > 0 ? ((double) charHeight * plane.getCanvasHeight() / (plane.getScreenRows() * 16.0)) : 14.0;
 
-        int totalW = textLen * (charWidth > 0 ? charWidth : 9);
-        int totalH = (charHeight > 0 ? charHeight : 14);
-        trackPoint(startX, startY);
-        trackPoint(startX + totalW, startY + totalH);
-        trackPoint(startX + totalW, startY - totalH);
+        int cellW = (charWidth > 0 ? charWidth : 9);
+        int cellH = (charHeight > 0 ? charHeight : 16);
+        switch (charDir) {
+            case GocaConstants.CD_TB:
+                trackPoint(startX, startY);
+                trackPoint(startX + cellW, startY - textLen * cellH);
+                break;
+            case GocaConstants.CD_RL:
+                trackPoint(startX, startY);
+                trackPoint(startX - textLen * cellW, startY + cellH);
+                break;
+            case GocaConstants.CD_BT:
+                trackPoint(startX, startY);
+                trackPoint(startX + cellW, startY + textLen * cellH);
+                break;
+            case GocaConstants.CD_LR:
+            case GocaConstants.CD_DEFAULT:
+            default:
+                trackPoint(startX, startY);
+                trackPoint(startX + textLen * cellW, startY + cellH);
+                break;
+        }
 
-        if (charSet != 0 && programSymbolManager != null) {
+        if (charSet == 0xF8 || charPrecision == GocaConstants.CP_STROKE) {
+            char[] chars = new char[textLen];
+            for (int i = 0; i < textLen; i++) {
+                chars[i] = EbcdicTranslator.ebcdicToAscii(data[pos + i]);
+            }
+            String text = new String(chars);
+            plane.drawVectorText(plane.mapXDouble(startX), plane.mapYDouble(startY), text,
+                                 curColor, cw, ch, charDir, charAngle);
+        } else if (charSet != 0 && programSymbolManager != null) {
             for (int i = 0; i < textLen; i++) {
                 int code = data[pos + i] & 0xFF;
                 double px = plane.mapXDouble(startX);
-                double py = plane.mapYDouble(startY) - ch;
+                double py = plane.mapYDouble(startY);
                 ProgramSymbolSet.SymbolSlot slot = programSymbolManager.getSymbol(charSet, code);
                 if (slot != null) {
                     int[] rgb = slot.getRgbPixels(curColor, 0);
                     int symW = slot.getWidth();
                     int symH = slot.getHeight();
                     int ipx = (int) Math.round(px);
-                    int ipy = (int) Math.round(py);
+                    int ipy = (int) Math.round(py - ch);
                     int icw = (int) Math.round(cw);
                     int ich = (int) Math.round(ch);
                     for (int dy = 0; dy < ich; dy++) {
@@ -1402,33 +1353,42 @@ public class GocaDecoder {
                             }
                         }
                     }
-                } else {
-                    char c = EbcdicTranslator.ebcdicToAscii(data[pos + i]);
-                    plane.drawVectorText(px, py, String.valueOf(c), curColor, cw, ch, charDir, charAngle);
                 }
                 startX += (charWidth > 0 ? charWidth : 9);
             }
             curX = startX;
             curY = startY;
             return;
-        }
-
-        char[] chars = new char[textLen];
-        for (int i = 0; i < textLen; i++) {
-            chars[i] = EbcdicTranslator.ebcdicToAscii(data[pos + i]);
-        }
-        String text = new String(chars);
-
-        if (charPrecision == GocaConstants.CP_STROKE) {
-            plane.drawVectorText(plane.mapXDouble(startX), plane.mapYDouble(startY) - ch, text,
-                                 curColor, cw, ch, charDir, charAngle);
         } else {
-            plane.drawText(plane.mapXDouble(startX), plane.mapYDouble(startY) - ch, text,
+            char[] chars = new char[textLen];
+            for (int i = 0; i < textLen; i++) {
+                chars[i] = EbcdicTranslator.ebcdicToAscii(data[pos + i]);
+            }
+            String text = new String(chars);
+            plane.drawText(plane.mapXDouble(startX), plane.mapYDouble(startY), text,
                            curColor, cw, ch, charDir, charAngle);
         }
 
-        curX = startX + (textLen * (charWidth > 0 ? charWidth : 9));
-        curY = startY;
+        switch (charDir) {
+            case GocaConstants.CD_TB:
+                curX = startX;
+                curY = startY - (textLen * (charHeight > 0 ? charHeight : 16));
+                break;
+            case GocaConstants.CD_RL:
+                curX = startX - (textLen * (charWidth > 0 ? charWidth : 9));
+                curY = startY;
+                break;
+            case GocaConstants.CD_BT:
+                curX = startX;
+                curY = startY + (textLen * (charHeight > 0 ? charHeight : 16));
+                break;
+            case GocaConstants.CD_LR:
+            case GocaConstants.CD_DEFAULT:
+            default:
+                curX = startX + (textLen * (charWidth > 0 ? charWidth : 9));
+                curY = startY;
+                break;
+        }
     }
 
     /**

lib3270j/src/main/java/haus/nightmare/lib3270j/graphics/GraphicsPlane.java

@@ -760,11 +760,6 @@ public class GraphicsPlane {
                                  (double) px[offset + i + 1], (double) py[offset + i + 1],
                                  boundaryColorArgb, lineType, lineWidth);
                     }
-                    if (pLen >= 3 && (px[offset] != px[offset + pLen - 1] || py[offset] != py[offset + pLen - 1])) {
-                        drawLine((double) px[offset + pLen - 1], (double) py[offset + pLen - 1],
-                                 (double) px[offset], (double) py[offset],
-                                 boundaryColorArgb, lineType, lineWidth);
-                    }
                 }
                 offset += pLen;
             }
@@ -885,10 +880,15 @@ public class GraphicsPlane {
         if (text == null || text.isEmpty()) return;
         int color = (colorArgb != 0) ? colorArgb : GocaConstants.GOCA_COLORS[0];
 
-        double curX = x;
-        double curY = y;
         double cw = cellWidth > 0 ? cellWidth : 12.0;
         double ch = cellHeight > 0 ? cellHeight : 20.0;
+        double curX = x;
+        double curY = y;
+        if (dir == GocaConstants.CD_TB) {
+            curY += ch;
+        } else if (dir == GocaConstants.CD_RL) {
+            curX -= cw;
+        }
 
         for (int i = 0; i < text.length(); i++) {
             char c = text.charAt(i);
@@ -942,7 +942,7 @@ public class GraphicsPlane {
                         int vx = ((VectorSymbolData.vss_data[dataPtr + p * 4] & 0xFF) << 8) | (VectorSymbolData.vss_data[dataPtr + p * 4 + 1] & 0xFF);
                         int vy = ((VectorSymbolData.vss_data[dataPtr + p * 4 + 2] & 0xFF) << 8) | (VectorSymbolData.vss_data[dataPtr + p * 4 + 3] & 0xFF);
                         px[p] = x + ((double) vx / VectorSymbolData.VSS_WIDTH) * cw;
-                        py[p] = y + ((double) (VectorSymbolData.VSS_HEIGHT - vy) / VectorSymbolData.VSS_HEIGHT) * ch;
+                        py[p] = y - ((double) vy / VectorSymbolData.VSS_HEIGHT) * ch;
                         ipx[p] = (int) Math.round(px[p]);
                         ipy[p] = (int) Math.round(py[p]);
                     }

lib3270j/src/main/java/haus/nightmare/lib3270j/input/InputProcessor.java

@@ -177,6 +177,10 @@ public class InputProcessor {
      */
     public void sendAid(int aidCode) {
         System.err.println("sendAid called: 0x" + Integer.toHexString(aidCode) + " locked=" + keyboardLocked);
+        if (aidCode == AID_SYSREQ) {
+            sysReq();
+            return;
+        }
         if (keyboardLocked && aidCode != AID_CLEAR) {
             System.err.println("Keyboard locked, dropping AID");
             return;
@@ -233,6 +237,86 @@ public class InputProcessor {
             return;
         }
 
+        if (gocaDecoder != null && gocaDecoder.isGraphicsCursorActive()) {
+            int gx = gocaDecoder.getGraphicCursorX();
+            int gy = gocaDecoder.getGraphicCursorY();
+            int cols = (screen != null && screen.getCols() > 0) ? screen.getCols() : 80;
+            int numRows = (screen != null && screen.getRows() > 0) ? screen.getRows() : 24;
+            int cursorAddr = screen != null ? screen.getCursorAddress() : 0;
+            int row = cursorAddr / cols;
+            int col = cursorAddr % cols;
+
+            byte[] sf = haus.nightmare.lib3270j.graphics.GraphicInputBuilder.buildGraphicInput(
+                gx, gy, row, col, aidCode, false, false, false
+            );
+
+            StringBuilder sfHex = new StringBuilder();
+            for (byte b : sf) {
+                sfHex.append(String.format("%02X ", b & 0xFF));
+            }
+            log.info(String.format(
+                "sendAid (graphic): goca=(%d, %d) row=%d col=%d cursorAddr=%d aid=0x%02X SF_HEX=[%s]",
+                gx, gy, row, col, cursorAddr, aidCode, sfHex.toString().trim()
+            ));
+
+            ByteArrayOutputStream out = new ByteArrayOutputStream();
+
+            // Structured Field AID (0x88) + 56-byte Graphic Input SF
+            out.write(AID_SF);
+            try {
+                out.write(sf);
+            } catch (java.io.IOException ignored) {}
+
+            // Trailing AID + cursor address
+            out.write(aidCode);
+            byte[] caddr = encodeAddress(cursorAddr, numRows, cols);
+            out.write(caddr[0] & 0xFF);
+            out.write(caddr[1] & 0xFF);
+
+            if (aidCode == AID_PA1 || aidCode == AID_PA2 || aidCode == AID_PA3) {
+                sendAidResponse(out.toByteArray());
+                return;
+            }
+
+            if (screen.isFormatted()) {
+                int size = screen.getRows() * screen.getCols();
+                for (int i = 0; i < size; i++) {
+                    ExtendedAttribute ea = screen.getCell(i);
+                    if (ea.isFieldAttribute() && faIsModified(ea.fa & 0xFF)) {
+                        int fieldStart = (i + 1) % size;
+
+                        // Always send SBA and address of first character in field
+                        out.write(ORDER_SBA);
+                        byte[] addr = encodeAddress(fieldStart, screen.getRows(), screen.getCols());
+                        out.write(addr[0] & 0xFF);
+                        out.write(addr[1] & 0xFF);
+
+                        // Send all non-null characters in field (suppressing 0x00)
+                        int pos = fieldStart;
+                        while (!screen.getCell(pos).isFieldAttribute()) {
+                            int b = screen.getCell(pos).ec & 0xFF;
+                            if (b != 0x00) {
+                                out.write(b);
+                            }
+                            pos = (pos + 1) % size;
+                            if (pos == fieldStart) break;
+                        }
+                    }
+                }
+            } else {
+                int size = screen.getRows() * screen.getCols();
+                for (int i = 0; i < size; i++) {
+                    int b = screen.getCell(i).ec & 0xFF;
+                    if (b != 0x00) {
+                        out.write(b);
+                    }
+                }
+            }
+
+            sendAidResponse(out.toByteArray());
+            return;
+        }
+
         if (aidCode == AID_PA1 || aidCode == AID_PA2 || aidCode == AID_PA3) {
             // PA keys: send AID + optional PID + cursor address only (no modified data)
             ByteArrayOutputStream out = new ByteArrayOutputStream();
@@ -358,21 +442,12 @@ public class InputProcessor {
         if (gocaDecoder != null && gocaDecoder.isGraphicsCursorActive()) {
             int gx = gocaDecoder.getGraphicCursorX();
             int gy = gocaDecoder.getGraphicCursorY();
-            int cursorAddr = screen != null ? screen.getCursorAddress() : 0;
             int cols = (screen != null && screen.getCols() > 0) ? screen.getCols() : 80;
+            int numRows = (screen != null && screen.getRows() > 0) ? screen.getRows() : 24;
+            int cursorAddr = screen != null ? screen.getCursorAddress() : 0;
             int row = cursorAddr / cols;
             int col = cursorAddr % cols;
 
-            if (gocaDecoder.getGraphicsPlane() != null) {
-                int px = gocaDecoder.getGraphicsPlane().mapX(gx);
-                int py = gocaDecoder.getGraphicsPlane().mapY(gy);
-                int canvasW = gocaDecoder.getGraphicsPlane().getCanvasWidth();
-                int canvasH = gocaDecoder.getGraphicsPlane().getCanvasHeight();
-                int numRows = (screen != null && screen.getRows() > 0) ? screen.getRows() : 43;
-                if (canvasH > 0) row = (py * numRows) / canvasH;
-                if (canvasW > 0) col = (px * cols) / canvasW;
-            }
-
             byte[] sf = haus.nightmare.lib3270j.graphics.GraphicInputBuilder.buildGraphicInput(
                 gx, gy, row, col, button, true, isShift, isCtrl
             );
@@ -382,8 +457,8 @@ public class InputProcessor {
                 sfHex.append(String.format("%02X ", b & 0xFF));
             }
             log.info(String.format(
-                "sendGraphicMouseAid: goca=(%d, %d) row=%d col=%d btn=%d shift=%b ctrl=%b SF_HEX=[%s]",
-                gx, gy, row, col, button, isShift, isCtrl, sfHex.toString().trim()
+                "sendGraphicMouseAid: goca=(%d, %d) row=%d col=%d cursorAddr=%d btn=%d shift=%b ctrl=%b SF_HEX=[%s]",
+                gx, gy, row, col, cursorAddr, button, isShift, isCtrl, sfHex.toString().trim()
             ));
 
             // Structured Field AID (0x88) + 56-byte Graphic Input SF
@@ -394,7 +469,7 @@ public class InputProcessor {
 
             // Trailing AID + cursor address + modified fields matching HOD DS3270.sendMouseAid
             out.write(aidCode);
-            byte[] caddr = encodeAddress(screen.getCursorAddress(), screen.getRows(), screen.getCols());
+            byte[] caddr = encodeAddress(cursorAddr, numRows, cols);
             out.write(caddr[0] & 0xFF);
             out.write(caddr[1] & 0xFF);
 
@@ -755,7 +830,11 @@ public class InputProcessor {
 
     /** SysReq key. */
     public void sysReq() {
-        reset();
+        if (fsm != null && fsm.isTn3270eNegotiated()) {
+            fsm.handleSysReq();
+        } else {
+            reset();
+        }
     }
 
     /** Reset (unlock keyboard, cancel insert mode). */

lib3270j/src/main/java/haus/nightmare/lib3270j/protocol/DS3270Constants.java

@@ -208,29 +208,40 @@ public final class DS3270Constants {
     public static final int SF_TRANSFER_DATA  = 0xd0;
 
     // ========== Query Reply codes ==========
-    public static final int QR_SUMMARY      = 0x80;
-    public static final int QR_USABLE_AREA  = 0x81;
-    public static final int QR_IMAGE        = 0x82;
-    public static final int QR_TEXT_PART    = 0x83;
-    public static final int QR_ALPHA_PART   = 0x84;
-    public static final int QR_CHARSETS     = 0x85;
-    public static final int QR_COLOR        = 0x86;
-    public static final int QR_HIGHLIGHTING = 0x87;
-    public static final int QR_REPLY_MODES  = 0x88;
-    public static final int QR_SAVE_RESTORE = 0x8c;
-    public static final int QR_DBCS_ASIA    = 0x91;
-    public static final int QR_DDM          = 0x95;
-    public static final int QR_TRANSPARENCY = 0x99;
-    public static final int QR_RPQNAMES     = 0xa1;
-    public static final int QR_IMP_PART     = 0xa6;
-    public static final int QR_RPQ_NAMES    = 0xa8;
-    public static final int QR_GRAPHICS     = 0xb0; // 3270-PC Vector Graphics
-    public static final int QR_GIMAGE       = 0xb1; // Image / Graphics Planes
-    public static final int QR_AUX_DEV      = 0xb2; // Auxiliary Device
-    public static final int QR_OEM_FMT      = 0xb3; // OEM Format
-    public static final int QR_GCOLOR       = 0xb4; // Graphic Color Table
-    public static final int QR_GSYMBOLS     = 0xb6; // Graphic Symbol Sets
-    public static final int QR_NULL         = 0xff;
+    public static final int QR_SUMMARY      = 0x80; // Summary
+    public static final int QR_USABLE_AREA  = 0x81; // Usable Area
+    public static final int QR_IMAGE        = 0x82; // Image (non-GOCA)
+    public static final int QR_TEXT_PART    = 0x83; // Text Partitions
+    public static final int QR_ALPHA_PART   = 0x84; // Alphanumeric Partitions
+    public static final int QR_CHARSETS     = 0x85; // Character Sets
+    public static final int QR_COLOR        = 0x86; // Color Table / Alphanumeric Color
+    public static final int QR_HIGHLIGHTING = 0x87; // Extended Highlighting
+    public static final int QR_REPLY_MODES  = 0x88; // Reply Modes
+    public static final int QR_OUTLINING    = 0x8c; // Field Outlining
+    public static final int QR_SAVE_RESTORE = 0x8c; // Legacy alias for QR_OUTLINING
+    public static final int QR_DBCS_ASIA    = 0x91; // DBCS Asia
+    public static final int QR_DDM          = 0x95; // Distributed Data Management
+    public static final int QR_AUXDA        = 0x99; // Auxiliary Devices
+    public static final int QR_FILE         = 0x9f; // File Transfer
+    public static final int QR_DEVICECHAR   = 0xa0; // Device Characteristics (Printer)
+    public static final int QR_RPQNAMES     = 0xa1; // RPQ Names (legacy)
+    public static final int QR_IMP_PART     = 0xa6; // Implicit Partition Sizes
+    public static final int QR_IMPLICIT     = 0xa6; // Alias for QR_IMP_PART
+    public static final int QR_TRANSPARENCY = 0xa8; // Background Transparency
+    public static final int QR_RPQ_NAMES    = 0xa8; // Legacy alias pointing to 0xa8
+    public static final int QR_SEGMENT      = 0xb0; // Segment Characteristics (3270-PC Vector Graphics)
+    public static final int QR_GRAPHICS     = 0xb0; // Legacy alias for QR_SEGMENT
+    public static final int QR_PROCEDURE    = 0xb1; // Procedure Characteristics (Image/GOCA)
+    public static final int QR_GIMAGE       = 0xb1; // Legacy alias for QR_PROCEDURE
+    public static final int QR_LINETYPE     = 0xb2; // Line Type Support (Aux Dev)
+    public static final int QR_AUX_DEV      = 0xb2; // Legacy alias for QR_LINETYPE
+    public static final int QR_PORT         = 0xb3; // Port Characteristics (OEM Format)
+    public static final int QR_OEM_FMT      = 0xb3; // Legacy alias for QR_PORT
+    public static final int QR_GRCOLOR      = 0xb4; // Graphic Color Table
+    public static final int QR_GCOLOR       = 0xb4; // Legacy alias for QR_GRCOLOR
+    public static final int QR_GRSYMBOLSET  = 0xb6; // Graphic Symbol Sets
+    public static final int QR_GSYMBOLS     = 0xb6; // Legacy alias for QR_GRSYMBOLSET
+    public static final int QR_NULL         = 0xff; // Query Reply Null (Unsupported)
 
     // ========== Screen model sizes ==========
     public static final int MODEL_2_ROWS = 24;

lib3270j/src/main/java/haus/nightmare/lib3270j/screen/ScreenBuffer.java

@@ -229,6 +229,11 @@ public class ScreenBuffer {
         this.cursorAddress = addr;
         this.displayCursorAddress = addr;
     }
+    public synchronized void setCursorPosition(int row, int col) {
+        int r = Math.max(0, Math.min(row, rows - 1));
+        int c = Math.max(0, Math.min(col, cols - 1));
+        setCursorAddress(r * cols + c);
+    }
     public int getCursorRow()                      { return cursorAddress / cols; }
     public int getCursorCol()                      { return cursorAddress % cols; }
 

lib3270j/src/main/java/haus/nightmare/lib3270j/telnet/TelnetFSM.java

@@ -402,11 +402,7 @@ public class TelnetFSM {
                 } else if (!myOpts[opt]) {
                     myOpts[opt] = true;
                     sendCommand(WILL, opt);
-                    // Start TN3270E sub-negotiation: send device type request
-                    if (!tn3270eDeviceTypeSent) {
-                        sendTN3270EDeviceTypeRequest();
-                        tn3270eDeviceTypeSent = true;
-                    }
+                    tn3270eDeviceTypeSent = false;
                 }
                 break;
 
@@ -863,25 +859,52 @@ public class TelnetFSM {
                         changeState(ConnectionState.CONNECTED_TN3270E);
                         tn3270eSubmode = TN3270ESubmode.E_3270;
                     }
-                    dsProcessor.processRecord(data, EH_SIZE, data.length - EH_SIZE, true);
-                    notifyScreenUpdate();
-                }
-                // Send positive response if required
-                if (eFuncs[FUNC_RESPONSES] && responseFlag == RSF_ALWAYS_RESPONSE) {
-                    sendTN3270EPositiveResponse(seqNumber);
+                    try {
+                        dsProcessor.processRecord(data, EH_SIZE, data.length - EH_SIZE, true);
+                        notifyScreenUpdate();
+                        // Send positive response if required
+                        if (eFuncs[FUNC_RESPONSES] && responseFlag == RSF_ALWAYS_RESPONSE) {
+                            sendTN3270EPositiveResponse(seqNumber);
+                        }
+                    } catch (Exception e) {
+                        log.log(Level.WARNING, "Error processing 3270 record", e);
+                        if (eFuncs[FUNC_RESPONSES] && (responseFlag == RSF_ALWAYS_RESPONSE || responseFlag == RSF_ERROR_RESPONSE)) {
+                            sendTN3270ENegativeResponse(seqNumber, NEG_OPERATION_CHECK);
+                        }
+                    }
+                } else {
+                    if (eFuncs[FUNC_RESPONSES] && responseFlag == RSF_ALWAYS_RESPONSE) {
+                        sendTN3270EPositiveResponse(seqNumber);
+                    }
                 }
                 break;
 
             case DT_SSCP_LU_DATA:
-                if (connectionState == ConnectionState.CONNECTED_UNBOUND) {
-                    // Clear screen on first SSCP-LU transition to remove stale data
-                    screenBuffer.clear();
+                if (connectionState != ConnectionState.CONNECTED_SSCP) {
+                    if (connectionState == ConnectionState.CONNECTED_UNBOUND) {
+                        // Clear screen on first SSCP-LU transition to remove stale data
+                        screenBuffer.clear();
+                    }
                     changeState(ConnectionState.CONNECTED_SSCP);
                     tn3270eSubmode = TN3270ESubmode.E_SSCP;
                 }
                 if (data.length > EH_SIZE) {
-                    dsProcessor.processSscpLuData(data, EH_SIZE, data.length - EH_SIZE);
-                    notifyScreenUpdate();
+                    try {
+                        dsProcessor.processSscpLuData(data, EH_SIZE, data.length - EH_SIZE);
+                        notifyScreenUpdate();
+                        if (eFuncs[FUNC_RESPONSES] && responseFlag == RSF_ALWAYS_RESPONSE) {
+                            sendTN3270EPositiveResponse(seqNumber);
+                        }
+                    } catch (Exception e) {
+                        log.log(Level.WARNING, "Error processing SSCP-LU record", e);
+                        if (eFuncs[FUNC_RESPONSES] && (responseFlag == RSF_ALWAYS_RESPONSE || responseFlag == RSF_ERROR_RESPONSE)) {
+                            sendTN3270ENegativeResponse(seqNumber, NEG_OPERATION_CHECK);
+                        }
+                    }
+                } else {
+                    if (eFuncs[FUNC_RESPONSES] && responseFlag == RSF_ALWAYS_RESPONSE) {
+                        sendTN3270EPositiveResponse(seqNumber);
+                    }
                 }
                 break;
 
@@ -899,7 +922,21 @@ public class TelnetFSM {
                 changeState(ConnectionState.CONNECTED_E_NVT);
                 tn3270eSubmode = TN3270ESubmode.E_NVT;
                 if (data.length > EH_SIZE) {
-                    processNVTData(data, EH_SIZE, data.length - EH_SIZE);
+                    try {
+                        processNVTData(data, EH_SIZE, data.length - EH_SIZE);
+                        if (eFuncs[FUNC_RESPONSES] && responseFlag == RSF_ALWAYS_RESPONSE) {
+                            sendTN3270EPositiveResponse(seqNumber);
+                        }
+                    } catch (Exception e) {
+                        log.log(Level.WARNING, "Error processing NVT record", e);
+                        if (eFuncs[FUNC_RESPONSES] && (responseFlag == RSF_ALWAYS_RESPONSE || responseFlag == RSF_ERROR_RESPONSE)) {
+                            sendTN3270ENegativeResponse(seqNumber, NEG_OPERATION_CHECK);
+                        }
+                    }
+                } else {
+                    if (eFuncs[FUNC_RESPONSES] && responseFlag == RSF_ALWAYS_RESPONSE) {
+                        sendTN3270EPositiveResponse(seqNumber);
+                    }
                 }
                 break;
 
@@ -1393,6 +1430,31 @@ public class TelnetFSM {
         return tn3270eBound || connectionState == ConnectionState.CONNECTED_3270;
     }
 
+    public boolean isTn3270eBound() {
+        return tn3270eBound;
+    }
+
+    public void handleSysReq() {
+        if (tn3270eNegotiated) {
+            byte[] ao = new byte[] { (byte) IAC, (byte) AO };
+            sendBytes(ao);
+            screenBuffer.clear();
+            screenBuffer.setCursorAddress(0);
+            screenBuffer.markAllChanged();
+            if (dsProcessor != null && dsProcessor.getInputProcessor() != null) {
+                dsProcessor.getInputProcessor().reset();
+            }
+            if (connectionState != ConnectionState.CONNECTED_SSCP) {
+                changeState(ConnectionState.CONNECTED_SSCP);
+                tn3270eSubmode = TN3270ESubmode.E_SSCP;
+            } else if (tn3270eBound) {
+                changeState(ConnectionState.CONNECTED_TN3270E);
+                tn3270eSubmode = TN3270ESubmode.E_3270;
+            }
+            notifyScreenUpdate();
+        }
+    }
+
     private static String tn3270eOpName(int op) {
         switch (op) {
             case OP_ASSOCIATE:   return "ASSOCIATE";

lib3270j/src/test/java/haus/nightmare/lib3270j/datastream/QueryReplyBuilderTest.java

@@ -22,10 +22,16 @@ public class QueryReplyBuilderTest {
         assertTrue(replies.length > 0);
         assertEquals((byte) AID_SF, replies[0]);
 
-        // In GraphicsMode.BOTH, Vector Graphics QR 0xB0 must be present
+        // In base query reply (buildAllQueryReplies), Summary (0x80) advertises QR_SEGMENT (0xB0)
+        // while the base reply itself contains base SFs (Usable Area, Charsets, Color, Highlighting, Reply Modes, DDM, AuxDA, ImpPart)
+        assertEquals(0x81, replies[3] & 0xFF); // SFID_QREPLY
+        assertEquals(QR_SUMMARY, replies[4] & 0xFF); // 0x80
+
+        // In buildCompleteQueryReplies, Vector Graphics QR 0xB0 structured field payload is present
+        byte[] completeReplies = qrBuilder.buildCompleteQueryReplies(80, 43, 80 * 43);
         boolean hasB0 = false;
-        for (int i = 0; i < replies.length - 3; i++) {
-            if ((replies[i] & 0xFF) == 0x81 && (replies[i + 1] & 0xFF) == QR_GRAPHICS) {
+        for (int i = 0; i < completeReplies.length - 3; i++) {
+            if ((completeReplies[i] & 0xFF) == 0x81 && (completeReplies[i + 1] & 0xFF) == QR_SEGMENT) {
                 hasB0 = true;
                 break;
             }
@@ -41,31 +47,27 @@ public class QueryReplyBuilderTest {
         assertTrue(replies.length > 0);
         assertEquals((byte) AID_SF, replies[0]);
 
-        // In GraphicsMode.NONE, Vector Graphics QR 0xB0 must NOT be present
-        boolean hasB0 = false;
-        for (int i = 0; i < replies.length - 3; i++) {
-            if ((replies[i] & 0xFF) == 0x81 && (replies[i + 1] & 0xFF) == QR_GRAPHICS) {
-                hasB0 = true;
-                break;
-            }
+        // In GraphicsMode.NONE, Vector Graphics QR 0xB0 must NOT be advertised in Summary
+        int sumLen = ((replies[1] & 0xFF) << 8) | (replies[2] & 0xFF);
+        for (int i = 5; i < 1 + sumLen; i++) {
+            assertNotEquals(QR_SEGMENT, replies[i] & 0xFF);
         }
-        assertFalse(hasB0);
     }
 
     @Test
     public void testBuildAllQueryRepliesWithVectorGraphics() {
         qrBuilder.setGraphicsMode(GraphicsMode.VECTOR_GRAPHICS);
-        byte[] replies = qrBuilder.buildAllQueryReplies(80, 43, 80 * 43);
+        byte[] replies = qrBuilder.buildCompleteQueryReplies(80, 43, 80 * 43);
         assertNotNull(replies);
 
-        // Vector Graphics QR 0xB0 and 0xB4 must be present
+        // In complete replies, Vector Graphics QR 0xB0 and 0xB4 must be present
         boolean hasB0 = false;
         boolean hasB4 = false;
         for (int i = 0; i < replies.length - 3; i++) {
-            if ((replies[i] & 0xFF) == 0x81 && (replies[i + 1] & 0xFF) == QR_GRAPHICS) {
+            if ((replies[i] & 0xFF) == 0x81 && (replies[i + 1] & 0xFF) == QR_SEGMENT) {
                 hasB0 = true;
             }
-            if ((replies[i] & 0xFF) == 0x81 && (replies[i + 1] & 0xFF) == QR_GCOLOR) {
+            if ((replies[i] & 0xFF) == 0x81 && (replies[i + 1] & 0xFF) == QR_GRCOLOR) {
                 hasB4 = true;
             }
         }
@@ -76,37 +78,39 @@ public class QueryReplyBuilderTest {
     @Test
     public void testBuildAllQueryRepliesWithBoth() {
         qrBuilder.setGraphicsMode(GraphicsMode.BOTH);
-        byte[] replies = qrBuilder.buildAllQueryReplies(80, 43, 80 * 43);
+        byte[] replies = qrBuilder.buildCompleteQueryReplies(80, 43, 80 * 43);
         assertNotNull(replies);
 
-        // Vector Graphics (0xB0) must be present and Charsets must have LoadPS (0x0A)
+        // Vector Graphics (0xB0) must be present and Charsets must be present (0x85)
         boolean hasB0 = false;
-        boolean hasCharsetsWithLoadPs = false;
+        boolean hasCharsets = false;
         for (int i = 0; i < replies.length - 3; i++) {
-            if ((replies[i] & 0xFF) == 0x81 && (replies[i + 1] & 0xFF) == QR_GRAPHICS) {
+            if ((replies[i] & 0xFF) == 0x81 && (replies[i + 1] & 0xFF) == QR_SEGMENT) {
                 hasB0 = true;
             }
-            if ((replies[i] & 0xFF) == 0x81 && (replies[i + 1] & 0xFF) == QR_CHARSETS) {
-                if (i + 6 < replies.length && (replies[i + 6] & 0xFF) == 0x0A) {
-                    hasCharsetsWithLoadPs = true;
-                }
+            if ((replies[i] & 0xFF) == 0x81 && (completeReplyIsCharsets(replies, i))) {
+                hasCharsets = true;
             }
         }
         assertTrue(hasB0);
-        assertTrue(hasCharsetsWithLoadPs);
+        assertTrue(hasCharsets);
+    }
+
+    private boolean completeReplyIsCharsets(byte[] replies, int i) {
+        return (replies[i + 1] & 0xFF) == QR_CHARSETS;
     }
 
     @Test
     public void testBuildAllQueryRepliesWithProgrammedSymbols() {
         qrBuilder.setGraphicsMode(GraphicsMode.PROGRAMMED_SYMBOLS);
-        byte[] replies = qrBuilder.buildAllQueryReplies(80, 43, 80 * 43);
+        byte[] replies = qrBuilder.buildCompleteQueryReplies(80, 43, 80 * 43);
         assertNotNull(replies);
 
-        // Charsets with LoadPS (0x0A) must be present, and QR_GRAPHICS must NOT be present
+        // Charsets with LoadPS (0x0A) must be present, and QR_SEGMENT must NOT be present
         boolean hasB0 = false;
         boolean hasCharsetsWithLoadPs = false;
         for (int i = 0; i < replies.length - 3; i++) {
-            if ((replies[i] & 0xFF) == 0x81 && (replies[i + 1] & 0xFF) == QR_GRAPHICS) {
+            if ((replies[i] & 0xFF) == 0x81 && (replies[i + 1] & 0xFF) == QR_SEGMENT) {
                 hasB0 = true;
             }
             if ((replies[i] & 0xFF) == 0x81 && (replies[i + 1] & 0xFF) == QR_CHARSETS) {
@@ -240,7 +244,7 @@ public class QueryReplyBuilderTest {
     @Test
     public void testQueryReplyImageAndRpqNames() {
         qrBuilder.setGraphicsMode(GraphicsMode.BOTH);
-        byte[] requested = new byte[] { (byte) QR_IMAGE, (byte) QR_RPQNAMES, (byte) QR_GIMAGE };
+        byte[] requested = new byte[] { (byte) QR_IMAGE, (byte) QR_TRANSPARENCY, (byte) QR_PROCEDURE };
         byte[] replies = qrBuilder.buildQueryReplies(requested, 80, 43, 80 * 43);
 
         assertNotNull(replies);
@@ -251,15 +255,69 @@ public class QueryReplyBuilderTest {
         assertEquals(0x81, replies[3] & 0xFF); // SFID_QREPLY
         assertEquals(QR_NULL, replies[4] & 0xFF); // 0xFF
 
-        // Second SF should be QR_RPQNAMES (0xA1) matching requested code
+        // Second SF should be QR_TRANSPARENCY (0xA8) matching requested code
         int pos2 = 1 + len1;
         int len2 = ((replies[pos2] & 0xFF) << 8) | (replies[pos2 + 1] & 0xFF);
         assertEquals(0x81, replies[pos2 + 2] & 0xFF);
-        assertEquals(QR_RPQNAMES, replies[pos2 + 3] & 0xFF); // 0xA1
+        assertEquals(QR_TRANSPARENCY, replies[pos2 + 3] & 0xFF); // 0xA8
 
-        // Third SF should be QR_GIMAGE (0xB1)
+        // Third SF should be QR_PROCEDURE (0xB1)
         int pos3 = pos2 + len2;
         assertEquals(0x81, replies[pos3 + 2] & 0xFF);
-        assertEquals(QR_GIMAGE, replies[pos3 + 3] & 0xFF); // 0xB1
+        assertEquals(QR_PROCEDURE, replies[pos3 + 3] & 0xFF); // 0xB1
+    }
+
+    @Test
+    public void testUsableAreaMetricsMatchHOD() {
+        qrBuilder.setGraphicsMode(GraphicsMode.VECTOR_GRAPHICS);
+        byte[] requested = new byte[] { (byte) QR_USABLE_AREA };
+        byte[] replies = qrBuilder.buildQueryReplies(requested, 80, 43, 80 * 43);
+
+        assertNotNull(replies);
+        assertEquals((byte) AID_SF, replies[0]);
+
+        // Length (2 bytes), SFID (0x81), QR_USABLE_AREA (0x81)
+        assertEquals(23, ((replies[1] & 0xFF) << 8) | (replies[2] & 0xFF));
+        assertEquals(0x81, replies[3] & 0xFF);
+        assertEquals(QR_USABLE_AREA, replies[4] & 0xFF);
+
+        // Flags: 12/14 bit addressing | Graphics (0x03), 0x00
+        assertEquals(0x03, replies[5] & 0xFF);
+        assertEquals(0x00, replies[6] & 0xFF);
+
+        // Usable width and height: 80, 43
+        assertEquals(80, ((replies[7] & 0xFF) << 8) | (replies[8] & 0xFF));
+        assertEquals(43, ((replies[9] & 0xFF) << 8) | (replies[10] & 0xFF));
+
+        // Units: 0x00 (Inches, matching IBM Host On-Demand DS3270.java)
+        assertEquals(0x00, replies[11] & 0xFF);
+
+        // Xr (4 bytes): 0x00010060 (96 dpi matching HOD)
+        int xr = ((replies[12] & 0xFF) << 24) | ((replies[13] & 0xFF) << 16) | ((replies[14] & 0xFF) << 8) | (replies[15] & 0xFF);
+        assertEquals(0x00010060, xr);
+
+        // Yr (4 bytes): 0x00010060 (96 dpi matching HOD)
+        int yr = ((replies[16] & 0xFF) << 24) | ((replies[17] & 0xFF) << 16) | ((replies[18] & 0xFF) << 8) | (replies[19] & 0xFF);
+        assertEquals(0x00010060, yr);
+
+        // AW and AH: 9 and 16
+        assertEquals(9, replies[20] & 0xFF);
+        assertEquals(16, replies[21] & 0xFF);
+
+        // Buffer size: 80 * 43 = 3440
+        assertEquals(80 * 43, ((replies[22] & 0xFF) << 8) | (replies[23] & 0xFF));
+    }
+
+    @Test
+    public void testGrSymbolSetMatchesHOD() {
+        qrBuilder.setGraphicsMode(GraphicsMode.VECTOR_GRAPHICS);
+        byte[] requested = new byte[] { (byte) QR_GRSYMBOLSET };
+        byte[] replies = qrBuilder.buildQueryReplies(requested, 80, 43, 80 * 43);
+
+        assertNotNull(replies);
+        assertEquals((byte) AID_SF, replies[0]);
+        assertEquals(33, ((replies[1] & 0xFF) << 8) | (replies[2] & 0xFF));
+        assertEquals(0x81, replies[3] & 0xFF);
+        assertEquals(QR_GRSYMBOLSET, replies[4] & 0xFF);
     }
 }

lib3270j/src/test/java/haus/nightmare/lib3270j/datastream/QueryReplyPhase2Test.java

@@ -0,0 +1,271 @@
+package haus.nightmare.lib3270j.datastream;
+
+import org.junit.jupiter.api.Test;
+import java.io.ByteArrayOutputStream;
+import java.util.ArrayList;
+import java.util.List;
+
+import haus.nightmare.lib3270j.TerminalModel;
+import haus.nightmare.lib3270j.charset.EbcdicTranslator;
+import haus.nightmare.lib3270j.graphics.GraphicsMode;
+import haus.nightmare.lib3270j.screen.ScreenBuffer;
+import static org.junit.jupiter.api.Assertions.*;
+import static haus.nightmare.lib3270j.protocol.DS3270Constants.*;
+
+public class QueryReplyPhase2Test {
+
+    private final EbcdicTranslator translator = new EbcdicTranslator();
+    private final ScreenBuffer screen = new ScreenBuffer(TerminalModel.IBM_3279_4, translator);
+    private final QueryReplyBuilder qrBuilder = new QueryReplyBuilder(screen);
+
+    /**
+     * Helper to parse structured fields out of a query reply stream.
+     */
+    private static class ParsedSF {
+        int length;
+        int sfid;
+        int qcode;
+        byte[] payload;
+
+        ParsedSF(int length, int sfid, int qcode, byte[] payload) {
+            this.length = length;
+            this.sfid = sfid;
+            this.qcode = qcode;
+            this.payload = payload;
+        }
+    }
+
+    private List<ParsedSF> parseQueryReplies(byte[] data) {
+        List<ParsedSF> list = new ArrayList<>();
+        assertNotNull(data);
+        assertTrue(data.length > 0);
+        assertEquals((byte) AID_SF, data[0]);
+
+        int pos = 1;
+        while (pos < data.length) {
+            int len = ((data[pos] & 0xFF) << 8) | (data[pos + 1] & 0xFF);
+            assertTrue(len >= 4, "Structured field length must be >= 4 at pos " + pos);
+            int sfid = data[pos + 2] & 0xFF;
+            int qcode = data[pos + 3] & 0xFF;
+            byte[] payload = new byte[len - 4];
+            System.arraycopy(data, pos + 4, payload, 0, payload.length);
+            list.add(new ParsedSF(len, sfid, qcode, payload));
+            pos += len;
+        }
+        assertEquals(data.length, pos, "All bytes in query reply must be accounted for");
+        return list;
+    }
+
+    @Test
+    public void testQCodeConstantsValuesMatchHod() {
+        assertEquals(0x80, QR_SUMMARY);
+        assertEquals(0x81, QR_USABLE_AREA);
+        assertEquals(0x84, QR_ALPHA_PART);
+        assertEquals(0x85, QR_CHARSETS);
+        assertEquals(0x86, QR_COLOR);
+        assertEquals(0x87, QR_HIGHLIGHTING);
+        assertEquals(0x88, QR_REPLY_MODES);
+        assertEquals(0x8C, QR_OUTLINING);
+        assertEquals(0x91, QR_DBCS_ASIA);
+        assertEquals(0x95, QR_DDM);
+        assertEquals(0x99, QR_AUXDA);
+        assertEquals(0xA6, QR_IMP_PART);
+        assertEquals(0xA8, QR_TRANSPARENCY);
+        assertEquals(0xB0, QR_SEGMENT);
+        assertEquals(0xB1, QR_PROCEDURE);
+        assertEquals(0xB2, QR_LINETYPE);
+        assertEquals(0xB3, QR_PORT);
+        assertEquals(0xB4, QR_GRCOLOR);
+        assertEquals(0xB6, QR_GRSYMBOLSET);
+        assertEquals(0xFF, QR_NULL);
+    }
+
+    @Test
+    public void testBaseGenericQueryReplySizeAndStructure() {
+        qrBuilder.setGraphicsMode(GraphicsMode.BOTH);
+        byte[] reply = qrBuilder.buildAllQueryReplies(80, 43, 80 * 43);
+        assertNotNull(reply);
+
+        List<ParsedSF> sfs = parseQueryReplies(reply);
+        // Base query reply must contain exactly 10 structured fields for SBCS:
+        // 0x80 (Summary), 0x81 (Usable Area), 0x84 (Alpha Partitions), 0x85 (Character Sets),
+        // 0x86 (Color), 0x87 (Highlighting), 0x88 (Reply Modes), 0x95 (DDM), 0x99 (AuxDA), 0xA6 (Implicit Part)
+        assertEquals(10, sfs.size());
+
+        assertEquals(QR_SUMMARY, sfs.get(0).qcode);
+        assertEquals(QR_USABLE_AREA, sfs.get(1).qcode);
+        assertEquals(QR_ALPHA_PART, sfs.get(2).qcode);
+        assertEquals(QR_CHARSETS, sfs.get(3).qcode);
+        assertEquals(QR_COLOR, sfs.get(4).qcode);
+        assertEquals(QR_HIGHLIGHTING, sfs.get(5).qcode);
+        assertEquals(QR_REPLY_MODES, sfs.get(6).qcode);
+        assertEquals(QR_DDM, sfs.get(7).qcode);
+        assertEquals(QR_AUXDA, sfs.get(8).qcode);
+        assertEquals(QR_IMP_PART, sfs.get(9).qcode);
+
+        // Verify that Vector Graphics SF payloads (0xA8, 0xB0..0xB6) are NOT sent in base reply
+        for (ParsedSF sf : sfs) {
+            assertNotEquals(QR_TRANSPARENCY, sf.qcode);
+            assertNotEquals(QR_SEGMENT, sf.qcode);
+            assertNotEquals(QR_PROCEDURE, sf.qcode);
+            assertNotEquals(QR_LINETYPE, sf.qcode);
+            assertNotEquals(QR_PORT, sf.qcode);
+            assertNotEquals(QR_GRCOLOR, sf.qcode);
+            assertNotEquals(QR_GRSYMBOLSET, sf.qcode);
+        }
+
+        // Verify summary structured field advertises full capabilities
+        byte[] summaryPayload = sfs.get(0).payload;
+        assertTrue(summaryPayload.length >= 17);
+        assertEquals(QR_SUMMARY, summaryPayload[0] & 0xFF);
+        assertEquals(QR_USABLE_AREA, summaryPayload[1] & 0xFF);
+    }
+
+    @Test
+    public void testTargetedQueryListAdmDrawResponse() {
+        qrBuilder.setGraphicsMode(GraphicsMode.BOTH);
+        // ADMDRAW vector graphics startup query list: 0x8C, 0xA8, 0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB6
+        byte[] requested = new byte[] {
+            (byte) QR_OUTLINING,    // 0x8C
+            (byte) QR_TRANSPARENCY, // 0xA8
+            (byte) QR_SEGMENT,      // 0xB0
+            (byte) QR_PROCEDURE,    // 0xB1
+            (byte) QR_LINETYPE,     // 0xB2
+            (byte) QR_PORT,         // 0xB3
+            (byte) QR_GRCOLOR,      // 0xB4
+            (byte) QR_GRSYMBOLSET   // 0xB6
+        };
+
+        byte[] replies = qrBuilder.buildQueryReplies(requested, 80, 43, 80 * 43);
+        List<ParsedSF> sfs = parseQueryReplies(replies);
+
+        // 8 requested QCODEs produce 11 SFs because QR_PORT emits 4 OEM format sub-fields
+        assertEquals(11, sfs.size());
+
+        // 1. QR_OUTLINING (0x8C): 10 bytes
+        assertEquals(QR_OUTLINING, sfs.get(0).qcode);
+        assertEquals(10, sfs.get(0).length);
+        assertArrayEquals(new byte[]{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }, sfs.get(0).payload);
+
+        // 2. QR_TRANSPARENCY (0xA8): 9 bytes
+        assertEquals(QR_TRANSPARENCY, sfs.get(1).qcode);
+        assertEquals(9, sfs.get(1).length);
+        assertArrayEquals(new byte[]{ 0x02, 0x00, (byte) 0xF0, (byte) 0xFF, (byte) 0xFF }, sfs.get(1).payload);
+
+        // 3. QR_SEGMENT (0xB0): 11 bytes
+        assertEquals(QR_SEGMENT, sfs.get(2).qcode);
+        assertEquals(11, sfs.get(2).length);
+        assertArrayEquals(new byte[]{ (byte) 0x80, 0x02, 0x00, 0x00, 0x00, (byte) 0xFC, 0x00 }, sfs.get(2).payload);
+
+        // 4. QR_PROCEDURE (0xB1): 21 bytes
+        assertEquals(QR_PROCEDURE, sfs.get(3).qcode);
+        assertEquals(21, sfs.get(3).length);
+        assertArrayEquals(new byte[]{
+            0x00, 0x01, 0x00, 0x00, 0x00, (byte) 0xFC, 0x00, 0x06, 0x40, 0x06, 0x40, 0x06, 0x01,
+            (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xF0
+        }, sfs.get(3).payload);
+
+        // 5. QR_LINETYPE (0xB2): 24 bytes
+        assertEquals(QR_LINETYPE, sfs.get(4).qcode);
+        assertEquals(24, sfs.get(4).length);
+        assertArrayEquals(new byte[]{
+            0x00, 0x09, 0x00, 0x07, 0x01, 0x01, 0x02, 0x02, 0x03, 0x03, 0x04, 0x04,
+            0x05, 0x05, 0x06, 0x06, 0x07, 0x07, 0x08, 0x08
+        }, sfs.get(4).payload);
+
+        // 6-9. QR_PORT (0xB3): 4 subfields (17, 15, 17, 15 bytes)
+        assertEquals(QR_PORT, sfs.get(5).qcode);
+        assertEquals(17, sfs.get(5).length);
+        assertEquals(QR_PORT, sfs.get(6).qcode);
+        assertEquals(15, sfs.get(6).length);
+        assertEquals(QR_PORT, sfs.get(7).qcode);
+        assertEquals(17, sfs.get(7).length);
+        assertEquals(QR_PORT, sfs.get(8).qcode);
+        assertEquals(15, sfs.get(8).length);
+
+        // 10. QR_GRCOLOR (0xB4): 109 bytes
+        assertEquals(QR_GRCOLOR, sfs.get(9).qcode);
+        assertEquals(109, sfs.get(9).length);
+
+        // 11. QR_GRSYMBOLSET (0xB6): 33 bytes
+        assertEquals(QR_GRSYMBOLSET, sfs.get(10).qcode);
+        assertEquals(33, sfs.get(10).length);
+    }
+
+    @Test
+    public void testUnsupportedQCodesEmitQrNull() {
+        qrBuilder.setGraphicsMode(GraphicsMode.BOTH);
+        byte[] requested = new byte[] { (byte) 0x12, (byte) 0x7E, (byte) 0xEE };
+        byte[] replies = qrBuilder.buildQueryReplies(requested, 80, 43, 80 * 43);
+
+        List<ParsedSF> sfs = parseQueryReplies(replies);
+        assertEquals(3, sfs.size());
+        for (ParsedSF sf : sfs) {
+            assertEquals(QR_NULL, sf.qcode);
+            assertEquals(4, sf.length);
+            assertEquals(0, sf.payload.length);
+        }
+    }
+
+    @Test
+    public void testDynamicCellDimensions() {
+        // In Vector Graphics mode, SDH must be 16 (0x10) for 3179G
+        qrBuilder.setGraphicsMode(GraphicsMode.VECTOR_GRAPHICS);
+        assertEquals(9, qrBuilder.getCharWidth());
+        assertEquals(16, qrBuilder.getCharHeight());
+
+        // In Text-only mode (GraphicsMode.NONE), SDH must be 12 (0x0C) for 3279-2
+        qrBuilder.setGraphicsMode(GraphicsMode.NONE);
+        assertEquals(9, qrBuilder.getCharWidth());
+        assertEquals(12, qrBuilder.getCharHeight());
+    }
+
+    @Test
+    public void testDataStreamProcessorQueryListDispatch() {
+        ByteArrayOutputStream captured = new ByteArrayOutputStream();
+        DataStreamProcessor processor = new DataStreamProcessor(screen, translator);
+        processor.setOutputSender(data -> {
+            try {
+                captured.write(data);
+            } catch (Exception e) {
+                fail(e);
+            }
+        });
+
+        // Test SF_RP_QUERY (0x02): generic query -> base query reply
+        byte[] genericQuery = new byte[] {
+            (byte) CMD_WSF,
+            0x00, 0x05, // Length = 5
+            (byte) SF_READ_PART, 0x00, // Partition = 0
+            (byte) SF_RP_QUERY // Type = 0x02
+        };
+
+        captured.reset();
+        processor.processRecord(genericQuery, 0, genericQuery.length, false);
+        byte[] sent = captured.toByteArray();
+        assertTrue(sent.length > 0);
+        assertEquals((byte) AID_SF, sent[0]);
+        List<ParsedSF> sfs = parseQueryReplies(sent);
+        assertEquals(10, sfs.size());
+
+        // Test SF_RP_QLIST (0x03) with SF_RPQ_LIST (0x00) and codes 0xB0, 0xB4
+        byte[] queryList = new byte[] {
+            (byte) CMD_WSF,
+            0x00, 0x08, // Length = 8
+            (byte) SF_READ_PART, 0x00,
+            (byte) SF_RP_QLIST,
+            (byte) SF_RPQ_LIST, // 0x00
+            (byte) QR_SEGMENT,  // 0xB0
+            (byte) QR_GRCOLOR   // 0xB4
+        };
+
+        captured.reset();
+        processor.processRecord(queryList, 0, queryList.length, false);
+        sent = captured.toByteArray();
+        assertTrue(sent.length > 0);
+        List<ParsedSF> listSfs = parseQueryReplies(sent);
+        assertEquals(2, listSfs.size());
+        assertEquals(QR_SEGMENT, listSfs.get(0).qcode);
+        assertEquals(QR_GRCOLOR, listSfs.get(1).qcode);
+    }
+}

lib3270j/src/test/java/haus/nightmare/lib3270j/graphics/GocaDecoderPhase5Test.java

@@ -71,14 +71,14 @@ public class GocaDecoderPhase5Test {
         GraphicsPlane plane = new GraphicsPlane(400, 300);
         GocaDecoder decoder = new GocaDecoder(plane);
 
-        // Segment 10 chains to Segment 11
+        // Segment 10 has bytes indicating nextId = 11
         ByteArrayOutputStream s10 = new ByteArrayOutputStream();
         s10.write(GocaConstants.G_BEGSEGM);
         s10.write(0x0C);
         s10.write(0x00); s10.write(0x00); s10.write(0x00); s10.write(0x0A); // Seg 10
         s10.write(0x00); s10.write(0x00);
         s10.write(0x00); s10.write(0x00); // flags
-        s10.write(0x00); s10.write(0x00); s10.write(0x00); s10.write(0x0B); // Next Seg ID = 11!
+        s10.write(0x00); s10.write(0x00); s10.write(0x00); s10.write(0x0B); // Next Seg ID = 11
         s10.write(GocaConstants.G_GSCOL); s10.write(0x01); // Blue
         s10.write(GocaConstants.G_GLINE); s10.write(0x08);
         s10.write(0x00); s10.write(10); s10.write(0x00); s10.write(10);
@@ -99,16 +99,16 @@ public class GocaDecoderPhase5Test {
         s11.write(0x00); s11.write(70); s11.write(0x00); s11.write(70);
         s11.write(GocaConstants.G_ENDSEGM); s11.write(0x00);
 
-        // Store Segment 11 first
+        // Decode Segment 11 first, then clear
         decoder.decodeGoca(s11.toByteArray(), 0, s11.toByteArray().length);
         plane.clear();
         assertFalse(plane.hasContent());
 
-        // Execute Segment 10; upon ENDSEGM, Segment 11 should be automatically chained!
+        // Execute Segment 10; per HOD architecture, ENDSEGM must NOT automatically execute Segment 11!
         decoder.decodeGoca(s10.toByteArray(), 0, s10.toByteArray().length);
         assertTrue(plane.hasContent());
 
-        // Verify both Blue (Seg 10) and Yellow (Seg 11) pixels exist
+        // Verify Blue (Seg 10) exists, and Yellow (Seg 11) is NOT drawn
         int blueArgb = GocaConstants.GOCA_COLORS[1];
         int yellowArgb = GocaConstants.GOCA_COLORS[6];
         boolean foundBlue = false;
@@ -118,7 +118,7 @@ public class GocaDecoderPhase5Test {
             if (p == yellowArgb) foundYellow = true;
         }
         assertTrue(foundBlue, "Expected Blue pixel from Segment 10");
-        assertTrue(foundYellow, "Expected Yellow pixel from chained Segment 11");
+        assertFalse(foundYellow, "Per HOD architecture, Segment 11 must NOT be automatically chained on ENDSEGM");
     }
 
     @Test

lib3270j/src/test/java/haus/nightmare/lib3270j/input/InputProcessorTest.java

@@ -451,4 +451,91 @@ public class InputProcessorTest {
         // SBA order at byte 3
         assertEquals((byte) ORDER_SBA, result[3]);
     }
+
+    @Test
+    public void testSendAidWhenGraphicsCursorActiveFraming() {
+        screen.erase(false);
+        screen.setCellFA(0, (byte) (FA_PRINTABLE | FA_MODIFY));
+        screen.getCell(1).ec = (byte) 0xC1; // 'A'
+        screen.setCellFA(5, (byte) (FA_PRINTABLE | FA_PROTECT));
+        screen.setCursorAddress(2);
+
+        haus.nightmare.lib3270j.graphics.GraphicsPlane plane = new haus.nightmare.lib3270j.graphics.GraphicsPlane(800, 600);
+        haus.nightmare.lib3270j.graphics.GocaDecoder goca = new haus.nightmare.lib3270j.graphics.GocaDecoder(plane);
+        goca.setGraphicsCursorActive(true);
+        goca.setGraphicCursorPosition(150, -80);
+
+        java.util.concurrent.atomic.AtomicReference<byte[]> sent = new java.util.concurrent.atomic.AtomicReference<>();
+        InputProcessor input = new InputProcessor(screen, translator, null) {
+            @Override
+            protected void sendAidResponse(byte[] data) {
+                sent.set(data);
+            }
+        };
+        input.setGocaDecoder(goca);
+
+        input.sendAid(AID_ENTER);
+
+        byte[] result = sent.get();
+        assertNotNull(result);
+        // Total expected length:
+        // 1 (AID_SF 0x88) + 56 (SF) + 1 (AID_ENTER 0x7D) + 2 (Cursor Addr) + 1 (SBA) + 2 (Field Addr) + 1 (Data 'A') = 64 bytes
+        assertEquals(64, result.length);
+        assertEquals((byte) AID_SF, result[0]);
+        // SF length = 52 (0x00 0x34) per IBM HOD / GOCA specification
+        assertEquals(0x00, result[1]);
+        assertEquals(0x34, result[2]);
+        // SF ID = 0x0F0F
+        assertEquals(0x0F, result[3]);
+        assertEquals(0x0F, result[4]);
+        // Coordinates in SF at index 1 + 24 = 25
+        int gx = (result[25] << 8) | (result[26] & 0xFF);
+        int gy = (result[27] << 8) | (result[28] & 0xFF);
+        assertEquals(150, (short) gx);
+        assertEquals(-80, (short) gy);
+        // Keyboard constants at index 1 + 31 = 32 and 1 + 33 = 34
+        assertEquals(0x07, result[32]);
+        assertEquals(0x07, result[34]);
+        assertEquals((byte) 0xFF, result[35]);
+        assertEquals((byte) AID_ENTER, result[36]);
+
+        // Trailing AID at index 57
+        assertEquals((byte) AID_ENTER, result[57]);
+        // Trailing SBA at 60
+        assertEquals((byte) ORDER_SBA, result[60]);
+        // Trailing field content 'A' at 63
+        assertEquals((byte) 0xC1, result[63]);
+    }
+
+    @Test
+    public void testSendAidPAWhenGraphicsCursorActiveFraming() {
+        screen.erase(false);
+        screen.setCellFA(0, (byte) (FA_PRINTABLE | FA_MODIFY));
+        screen.getCell(1).ec = (byte) 0xC1;
+        screen.setCursorAddress(2);
+
+        haus.nightmare.lib3270j.graphics.GraphicsPlane plane = new haus.nightmare.lib3270j.graphics.GraphicsPlane(800, 600);
+        haus.nightmare.lib3270j.graphics.GocaDecoder goca = new haus.nightmare.lib3270j.graphics.GocaDecoder(plane);
+        goca.setGraphicsCursorActive(true);
+        goca.setGraphicCursorPosition(100, 200);
+
+        java.util.concurrent.atomic.AtomicReference<byte[]> sent = new java.util.concurrent.atomic.AtomicReference<>();
+        InputProcessor input = new InputProcessor(screen, translator, null) {
+            @Override
+            protected void sendAidResponse(byte[] data) {
+                sent.set(data);
+            }
+        };
+        input.setGocaDecoder(goca);
+
+        input.sendAid(AID_PA1);
+
+        byte[] result = sent.get();
+        assertNotNull(result);
+        // 1 (AID_SF 0x88) + 56 (SF) + 1 (AID_PA1 0x6C) + 2 (Cursor Addr) = 60 bytes (no modified field data)
+        assertEquals(60, result.length);
+        assertEquals((byte) AID_SF, result[0]);
+        assertEquals((byte) AID_PA1, result[36]); // Keyboard AID in SF
+        assertEquals((byte) AID_PA1, result[57]); // Trailing AID
+    }
 }

lib3270j/src/test/java/haus/nightmare/lib3270j/input/Phase3InteractiveSelectionTest.java

@@ -0,0 +1,272 @@
+package haus.nightmare.lib3270j.input;
+
+import haus.nightmare.lib3270j.TerminalModel;
+import haus.nightmare.lib3270j.charset.EbcdicTranslator;
+import haus.nightmare.lib3270j.graphics.GddmCoordinateTransform;
+import haus.nightmare.lib3270j.graphics.GocaDecoder;
+import haus.nightmare.lib3270j.graphics.GraphicsPlane;
+import haus.nightmare.lib3270j.protocol.DS3270Constants;
+import haus.nightmare.lib3270j.screen.ScreenBuffer;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.awt.Point;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static haus.nightmare.lib3270j.protocol.DS3270Constants.*;
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * Verification test suite for Phase 3: Interactive Selection, Cursor Addressing & ADMDRAW Alignment.
+ */
+public class Phase3InteractiveSelectionTest {
+
+    private ScreenBuffer screen;
+    private EbcdicTranslator translator;
+
+    @BeforeEach
+    public void setUp() {
+        translator = new EbcdicTranslator();
+        screen = new ScreenBuffer(TerminalModel.IBM_3279_2, translator);
+    }
+
+    @Test
+    public void testScreenBufferSetCursorPosition() {
+        screen.setCursorPosition(5, 12);
+        assertEquals(5, screen.getCursorRow());
+        assertEquals(12, screen.getCursorCol());
+        assertEquals(5 * 80 + 12, screen.getCursorAddress());
+
+        // Test clamping
+        screen.setCursorPosition(-2, -5);
+        assertEquals(0, screen.getCursorRow());
+        assertEquals(0, screen.getCursorCol());
+        assertEquals(0, screen.getCursorAddress());
+
+        screen.setCursorPosition(100, 200);
+        assertEquals(23, screen.getCursorRow());
+        assertEquals(79, screen.getCursorCol());
+        assertEquals(23 * 80 + 79, screen.getCursorAddress());
+    }
+
+    @Test
+    public void testImmediateLightPenSelectionSpaceDesignator() {
+        // Unprotected selectable field at pos 0 with space designator (0x40)
+        screen.erase(false);
+        screen.setCellFA(0, (byte) (FA_PRINTABLE | FA_INT_NORM_SEL));
+        screen.getCell(1).ec = 0x40; // ' '
+        screen.getCell(1).ucs4 = ' ';
+        screen.getCell(2).ec = (byte) 0xC1; // 'A'
+        screen.getCell(2).ucs4 = 'A';
+        screen.setCellFA(10, (byte) (FA_PRINTABLE | FA_PROTECT));
+
+        AtomicReference<byte[]> sentData = new AtomicReference<>();
+        InputProcessor input = new InputProcessor(screen, translator, null) {
+            @Override
+            protected void sendAidResponse(byte[] data) {
+                sentData.set(data);
+            }
+        };
+
+        // Click at address 5 inside the field
+        boolean handled = input.lightPenSelect(5);
+        assertTrue(handled);
+        assertEquals(5, screen.getCursorAddress(), "Cursor should be positioned at clicked address");
+        assertTrue(faIsModified(screen.getCell(0).fa & 0xFF), "MDT should be set");
+
+        byte[] sent = sentData.get();
+        assertNotNull(sent);
+        assertEquals((byte) AID_SELECT, sent[0], "Immediate space designator must send AID_SELECT (0x7E)");
+
+        // Format: AID(1) + CursorAddr(2) + SBA(1) + DesignatorAddr(2) = 6 bytes (NO text content!)
+        assertEquals(6, sent.length, "AID_SELECT must NOT include field text content");
+        assertEquals((byte) ORDER_SBA, sent[3]);
+    }
+
+    @Test
+    public void testImmediateLightPenSelectionNullDesignator() {
+        // Unprotected selectable field at pos 0 with null designator (0x00)
+        screen.erase(false);
+        screen.setCellFA(0, (byte) (FA_PRINTABLE | FA_INT_NORM_SEL));
+        screen.getCell(1).ec = 0x00; // null
+        screen.getCell(1).ucs4 = 0;
+        screen.setCellFA(10, (byte) (FA_PRINTABLE | FA_PROTECT));
+
+        AtomicReference<byte[]> sentData = new AtomicReference<>();
+        InputProcessor input = new InputProcessor(screen, translator, null) {
+            @Override
+            protected void sendAidResponse(byte[] data) {
+                sentData.set(data);
+            }
+        };
+
+        boolean handled = input.lightPenSelect(2);
+        assertTrue(handled);
+        assertEquals(2, screen.getCursorAddress());
+        assertTrue(faIsModified(screen.getCell(0).fa & 0xFF));
+
+        byte[] sent = sentData.get();
+        assertNotNull(sent);
+        assertEquals((byte) AID_SELECT, sent[0]);
+    }
+
+    @Test
+    public void testImmediateEnterLightPenSelectionAmpersandDesignator() {
+        // Selectable field at pos 0 with '&' designator (0x50)
+        screen.erase(false);
+        screen.setCellFA(0, (byte) (FA_PRINTABLE | FA_INT_NORM_SEL));
+        screen.getCell(1).ec = 0x50; // '&'
+        screen.getCell(1).ucs4 = '&';
+        screen.getCell(2).ec = (byte) 0xC1; // 'A'
+        screen.getCell(2).ucs4 = 'A';
+        screen.setCellFA(10, (byte) (FA_PRINTABLE | FA_PROTECT));
+
+        AtomicReference<byte[]> sentData = new AtomicReference<>();
+        InputProcessor input = new InputProcessor(screen, translator, null) {
+            @Override
+            protected void sendAidResponse(byte[] data) {
+                sentData.set(data);
+            }
+        };
+
+        boolean handled = input.lightPenSelect(1);
+        assertTrue(handled);
+        assertEquals(1, screen.getCursorAddress());
+        assertTrue(faIsModified(screen.getCell(0).fa & 0xFF));
+
+        byte[] sent = sentData.get();
+        assertNotNull(sent);
+        assertEquals((byte) AID_ENTER, sent[0], "Immediate '&' designator must send AID_ENTER (0x7D)");
+    }
+
+    @Test
+    public void testDeferredLightPenSelectionToggle() {
+        // Protected selectable field at pos 0 with '?' designator (0x6F)
+        screen.erase(false);
+        screen.setCellFA(0, (byte) (FA_PRINTABLE | FA_PROTECT | FA_INT_NORM_SEL));
+        screen.getCell(1).ec = 0x6F; // '?'
+        screen.getCell(1).ucs4 = '?';
+        screen.getCell(2).ec = (byte) 0xC3; // 'C'
+        screen.getCell(2).ucs4 = 'C';
+        screen.setCellFA(10, (byte) (FA_PRINTABLE | FA_PROTECT));
+
+        AtomicReference<byte[]> sentData = new AtomicReference<>();
+        InputProcessor input = new InputProcessor(screen, translator, null) {
+            @Override
+            protected void sendAidResponse(byte[] data) {
+                sentData.set(data);
+            }
+        };
+
+        // First click: toggle '?' -> '>' and set MDT (no transmission)
+        boolean handled = input.lightPenSelect(1);
+        assertTrue(handled);
+        assertEquals((byte) 0x6E, screen.getCell(1).ec, "Designator must change to '>' (0x6E)");
+        assertEquals('>', (char) screen.getCell(1).ucs4);
+        assertTrue(faIsModified(screen.getCell(0).fa & 0xFF), "MDT must be set");
+        assertNull(sentData.get(), "Deferred selection must NOT transmit immediately");
+
+        // Now user presses Enter: transmits AID_ENTER with '>' and modified field
+        input.sendAid(AID_ENTER);
+        byte[] sent = sentData.get();
+        assertNotNull(sent);
+        assertEquals((byte) AID_ENTER, sent[0]);
+        assertEquals((byte) ORDER_SBA, sent[3]);
+        assertEquals((byte) 0x6E, sent[6], "Sent field content must contain '>' (0x6E)");
+        assertEquals((byte) 0xC3, sent[7], "Sent field content must contain 'C'");
+
+        sentData.set(null);
+
+        // Second click: toggle '>' -> '?' and clear MDT
+        handled = input.lightPenSelect(1);
+        assertTrue(handled);
+        assertEquals((byte) 0x6F, screen.getCell(1).ec, "Designator must change back to '?' (0x6F)");
+        assertEquals('?', (char) screen.getCell(1).ucs4);
+        assertFalse(faIsModified(screen.getCell(0).fa & 0xFF), "MDT must be cleared");
+        assertNull(sentData.get(), "Deferred deselection must NOT transmit immediately");
+    }
+
+    @Test
+    public void testSendGraphicMouseAidCoordinatesAndCursorSynchronization() {
+        screen.erase(false);
+        screen.setCellFA(0, (byte) (FA_PRINTABLE | FA_MODIFY));
+        screen.getCell(1).ec = (byte) 0xD6; // 'O'
+        screen.getCell(2).ec = (byte) 0xD2; // 'K'
+        screen.setCellFA(10, (byte) (FA_PRINTABLE | FA_PROTECT));
+
+        // Click at row 3, col 15 -> address = 3 * 80 + 15 = 255
+        screen.setCursorPosition(3, 15);
+
+        GraphicsPlane plane = new GraphicsPlane(720, 384);
+        plane.setScreenDimensions(80, 24);
+        GocaDecoder goca = new GocaDecoder(plane);
+        goca.setGraphicsCursorActive(true);
+        goca.setGraphicCursorPosition(200, 100);
+
+        AtomicReference<byte[]> sentData = new AtomicReference<>();
+        InputProcessor input = new InputProcessor(screen, translator, null) {
+            @Override
+            protected void sendAidResponse(byte[] data) {
+                sentData.set(data);
+            }
+        };
+        input.setGocaDecoder(goca);
+
+        input.sendGraphicMouseAid(AID_ENTER, 1, false, false);
+
+        byte[] sent = sentData.get();
+        assertNotNull(sent);
+
+        // AID_SF (0x88) + 56 SF bytes + AID_ENTER (0x7D) + 2 cursor bytes + SBA + ...
+        assertEquals((byte) AID_SF, sent[0]);
+        assertEquals(0x00, sent[1]);
+        assertEquals(0x34, sent[2]); // 52-byte SF length mask
+
+        // Coordinate verification in SF
+        int gx = (sent[25] << 8) | (sent[26] & 0xFF);
+        int gy = (sent[27] << 8) | (sent[28] & 0xFF);
+        assertEquals(200, (short) gx);
+        assertEquals(100, (short) gy);
+
+        // Trailing AID and cursor SBA at index 57-59
+        assertEquals((byte) AID_ENTER, sent[57]);
+        byte[] expectedCursor = encodeAddress(3 * 80 + 15, 24, 80);
+        assertEquals(expectedCursor[0], sent[58], "Trailing cursor address byte 0 must match clicked row/col");
+        assertEquals(expectedCursor[1], sent[59], "Trailing cursor address byte 1 must match clicked row/col");
+    }
+
+    @Test
+    public void testGddmCoordinateTransformModel2AndModel4() {
+        // Model 2 (80x24)
+        GddmCoordinateTransform t2 = new GddmCoordinateTransform(80, 24, 9, 16);
+        assertEquals(720, t2.getTotalWidth());
+        assertEquals(384, t2.getTotalHeight());
+        assertEquals(360, t2.getXMax());
+        assertEquals(191, t2.getYMax());
+
+        // Row 0 click (y in [0..15] out of 384)
+        Point gocaTop = t2.screenPixelToGoca(0, 0, 0, 0, 9, 16);
+        assertEquals(-360, gocaTop.x);
+        assertEquals(191, gocaTop.y, "Top row in Model 2 must start at gy = 191");
+
+        // Model 4 (80x43)
+        GddmCoordinateTransform t4 = new GddmCoordinateTransform(80, 43, 9, 16);
+        assertEquals(720, t4.getTotalWidth());
+        assertEquals(688, t4.getTotalHeight());
+        assertEquals(360, t4.getXMax());
+        assertEquals(343, t4.getYMax());
+
+        Point gocaTop4 = t4.screenPixelToGoca(0, 0, 0, 0, 9, 16);
+        assertEquals(-360, gocaTop4.x);
+        assertEquals(343, gocaTop4.y, "Top row in Model 4 must start at gy = 343");
+
+        // Center roundtrip
+        Point centerBase = t4.gocaToBase(0, 0);
+        assertEquals(360, centerBase.x);
+        assertEquals(343, centerBase.y);
+        Point centerGoca = t4.baseToGoca(centerBase.x, centerBase.y);
+        assertEquals(0, centerGoca.x);
+        assertEquals(0, centerGoca.y);
+    }
+}

lib3270j/src/test/java/haus/nightmare/lib3270j/telnet/TelnetFSMPhase1Test.java

@@ -0,0 +1,347 @@
+package haus.nightmare.lib3270j.telnet;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import haus.nightmare.lib3270j.ConnectionConfig;
+import haus.nightmare.lib3270j.ConnectionState;
+import haus.nightmare.lib3270j.TerminalModel;
+import haus.nightmare.lib3270j.charset.EbcdicTranslator;
+import haus.nightmare.lib3270j.datastream.DataStreamProcessor;
+import haus.nightmare.lib3270j.input.InputProcessor;
+import haus.nightmare.lib3270j.protocol.DS3270Constants;
+import haus.nightmare.lib3270j.protocol.TelnetConstants;
+import haus.nightmare.lib3270j.protocol.TN3270EConstants;
+import haus.nightmare.lib3270j.screen.ScreenBuffer;
+
+import java.io.ByteArrayOutputStream;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static haus.nightmare.lib3270j.protocol.TelnetConstants.*;
+import static haus.nightmare.lib3270j.protocol.TN3270EConstants.*;
+
+public class TelnetFSMPhase1Test {
+
+    private ConnectionConfig config;
+    private ScreenBuffer screenBuffer;
+    private DataStreamProcessor dsProcessor;
+    private InputProcessor inputProcessor;
+    private TelnetFSM fsm;
+    private MockConnection connection;
+    private EbcdicTranslator translator;
+
+    private static class MockConnection extends TelnetConnection {
+        final List<byte[]> sentData = new ArrayList<>();
+
+        MockConnection(ConnectionConfig config, TelnetFSM fsm) {
+            super(config, fsm);
+        }
+
+        @Override
+        public synchronized void sendRaw(byte[] data) {
+            sentData.add(data.clone());
+        }
+
+        @Override
+        public synchronized void sendRaw(byte[] data, int offset, int length) {
+            byte[] b = new byte[length];
+            System.arraycopy(data, offset, b, 0, length);
+            sentData.add(b);
+        }
+    }
+
+    @BeforeEach
+    public void setup() {
+        translator = new EbcdicTranslator();
+        config = new ConnectionConfig("localhost", 23, TerminalModel.IBM_3279_4);
+        screenBuffer = new ScreenBuffer(TerminalModel.IBM_3279_4, translator);
+        dsProcessor = new DataStreamProcessor(screenBuffer, translator);
+        fsm = new TelnetFSM(config, screenBuffer, dsProcessor);
+        inputProcessor = new InputProcessor(screenBuffer, translator, fsm);
+        dsProcessor.setInputProcessor(inputProcessor);
+        connection = new MockConnection(config, fsm);
+        fsm.setConnection(connection);
+    }
+
+    private void feedBytes(int... bytes) {
+        for (int b : bytes) {
+            fsm.feedByte(b & 0xFF);
+        }
+    }
+
+    @Test
+    public void testTn3270eSequencingWaitsForSendDeviceType() {
+        config.setTn3270eEnabled(true);
+        fsm.onConnected();
+        connection.sentData.clear();
+
+        // 1. Server sends DO TN3270E
+        feedBytes(IAC, DO, TELOPT_TN3270E);
+
+        // Client must reply IAC WILL TN3270E only, and MUST NOT emit unsolicited DEVICE-TYPE REQUEST
+        assertEquals(1, connection.sentData.size(), "Only WILL TN3270E should be sent initially");
+        byte[] willPkt = connection.sentData.get(0);
+        assertArrayEquals(new byte[] { (byte) IAC, (byte) WILL, (byte) TELOPT_TN3270E }, willPkt);
+        connection.sentData.clear();
+
+        // 2. Server sends IAC SB TN3270E SEND DEVICE-TYPE IAC SE
+        feedBytes(IAC, SB, TELOPT_TN3270E, OP_SEND, OP_DEVICE_TYPE, IAC, SE);
+
+        // Client must now send IAC SB TN3270E DEVICE-TYPE REQUEST <type> IAC SE
+        assertEquals(1, connection.sentData.size(), "Client should send DEVICE-TYPE REQUEST after SEND command");
+        byte[] reqPkt = connection.sentData.get(0);
+        assertTrue((reqPkt[0] & 0xFF) == IAC && (reqPkt[1] & 0xFF) == SB && (reqPkt[2] & 0xFF) == TELOPT_TN3270E);
+        assertEquals(OP_DEVICE_TYPE, reqPkt[3] & 0xFF);
+        assertEquals(OP_REQUEST, reqPkt[4] & 0xFF);
+        String devType = new String(reqPkt, 5, reqPkt.length - 7);
+        assertEquals("IBM-3279-4-E", devType);
+    }
+
+    @Test
+    public void testTn3270eResponseSignalingAlwaysResponse() {
+        config.setTn3270eEnabled(true);
+        fsm.onConnected();
+
+        // Negotiate TN3270E
+        feedBytes(IAC, DO, TELOPT_TN3270E);
+        feedBytes(IAC, SB, TELOPT_TN3270E, OP_SEND, OP_DEVICE_TYPE, IAC, SE);
+        byte[] devTypeIs = new byte[]{
+            (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E,
+            0x02, 0x04, 'I', 'B', 'M', '-', '3', '2', '7', '9', '-', '4', '-', 'E',
+            (byte) IAC, (byte) SE
+        };
+        for (byte b : devTypeIs) fsm.feedByte(b & 0xFF);
+
+        // Functions: RESPONSES + BIND-IMAGE
+        byte[] funcsReq = new byte[]{
+            (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E,
+            (byte) OP_FUNCTIONS, (byte) OP_REQUEST,
+            (byte) FUNC_BIND_IMAGE, (byte) FUNC_RESPONSES,
+            (byte) IAC, (byte) SE
+        };
+        for (byte b : funcsReq) fsm.feedByte(b & 0xFF);
+        connection.sentData.clear();
+
+        // Send 3270 data record with ALWAYS_RESPONSE (0x02) and seq = 0x0042
+        int seq = 0x0042;
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        bos.write(DT_3270_DATA);       // byte 0: data type
+        bos.write(0x00);               // byte 1: request flag
+        bos.write(RSF_ALWAYS_RESPONSE);// byte 2: response flag (0x02)
+        bos.write((seq >> 8) & 0xFF);  // byte 3: seq hi
+        bos.write(seq & 0xFF);         // byte 4: seq lo
+        bos.write(0xF5);               // EraseWrite
+        bos.write(0xC3);               // WCC
+        bos.write(0x11); bos.write(0x40); bos.write(0x40); // SBA 0
+        bos.write(translator.unicodeToEbcdic('A'));
+        bos.write(IAC);
+        bos.write(EOR);
+
+        for (byte b : bos.toByteArray()) fsm.feedByte(b & 0xFF);
+
+        // Client must emit positive response: DT_RESPONSE (0x02), 0x00, RSF_POSITIVE_RESPONSE (0x00), seq, POS_DEVICE_END (0x00), IAC, EOR
+        boolean foundPositiveResponse = false;
+        for (byte[] pkt : connection.sentData) {
+            if (pkt.length >= 8 &&
+                (pkt[0] & 0xFF) == DT_RESPONSE &&
+                (pkt[2] & 0xFF) == RSF_POSITIVE_RESPONSE &&
+                ((((pkt[3] & 0xFF) << 8) | (pkt[4] & 0xFF)) == seq) &&
+                (pkt[5] & 0xFF) == POS_DEVICE_END &&
+                (pkt[6] & 0xFF) == IAC &&
+                (pkt[7] & 0xFF) == EOR) {
+                foundPositiveResponse = true;
+            }
+        }
+        assertTrue(foundPositiveResponse, "Expected positive response with matching sequence number for RSF_ALWAYS_RESPONSE");
+    }
+
+    @Test
+    public void testTn3270eResponseSignalingNoResponse() {
+        config.setTn3270eEnabled(true);
+        fsm.onConnected();
+
+        feedBytes(IAC, DO, TELOPT_TN3270E);
+        feedBytes(IAC, SB, TELOPT_TN3270E, OP_SEND, OP_DEVICE_TYPE, IAC, SE);
+        byte[] devTypeIs = new byte[]{
+            (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E,
+            0x02, 0x04, 'I', 'B', 'M', '-', '3', '2', '7', '9', '-', '4', '-', 'E',
+            (byte) IAC, (byte) SE
+        };
+        for (byte b : devTypeIs) fsm.feedByte(b & 0xFF);
+
+        byte[] funcsReq = new byte[]{
+            (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E,
+            (byte) OP_FUNCTIONS, (byte) OP_REQUEST,
+            (byte) FUNC_BIND_IMAGE, (byte) FUNC_RESPONSES,
+            (byte) IAC, (byte) SE
+        };
+        for (byte b : funcsReq) fsm.feedByte(b & 0xFF);
+        connection.sentData.clear();
+
+        // Send 3270 data record with NO_RESPONSE (0x00)
+        int seq = 0x0099;
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        bos.write(DT_3270_DATA);
+        bos.write(0x00);
+        bos.write(RSF_NO_RESPONSE); // 0x00
+        bos.write((seq >> 8) & 0xFF);
+        bos.write(seq & 0xFF);
+        bos.write(0xF5);
+        bos.write(0xC3);
+        bos.write(IAC);
+        bos.write(EOR);
+
+        for (byte b : bos.toByteArray()) fsm.feedByte(b & 0xFF);
+
+        // No response packets should be sent
+        assertEquals(0, connection.sentData.size(), "No response should be generated when RSF_NO_RESPONSE (0x00)");
+    }
+
+    @Test
+    public void testSysReqOutOfBandRoutingAndToggle() {
+        config.setTn3270eEnabled(true);
+        fsm.onConnected();
+
+        // Complete TN3270E negotiation
+        feedBytes(IAC, DO, TELOPT_TN3270E);
+        feedBytes(IAC, SB, TELOPT_TN3270E, OP_SEND, OP_DEVICE_TYPE, IAC, SE);
+        byte[] devTypeIs = new byte[]{
+            (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E,
+            0x02, 0x04, 'I', 'B', 'M', '-', '3', '2', '7', '9', '-', '4', '-', 'E',
+            (byte) IAC, (byte) SE
+        };
+        for (byte b : devTypeIs) fsm.feedByte(b & 0xFF);
+
+        byte[] funcsReq = new byte[]{
+            (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E,
+            (byte) OP_FUNCTIONS, (byte) OP_REQUEST,
+            (byte) FUNC_BIND_IMAGE, (byte) FUNC_RESPONSES, (byte) FUNC_SYSREQ,
+            (byte) IAC, (byte) SE
+        };
+        for (byte b : funcsReq) fsm.feedByte(b & 0xFF);
+
+        // Send BIND image to bind session
+        byte[] bindPacket = new byte[EH_SIZE + 35];
+        bindPacket[0] = DT_BIND_IMAGE;
+        bindPacket[1] = 0; bindPacket[2] = 0; bindPacket[3] = 0; bindPacket[4] = 1;
+        bindPacket[EH_SIZE + 24] = 0x02; // Model 2 (24x80)
+        ByteArrayOutputStream bStream = new ByteArrayOutputStream();
+        bStream.write(bindPacket, 0, bindPacket.length);
+        bStream.write(IAC);
+        bStream.write(EOR);
+        for (byte b : bStream.toByteArray()) fsm.feedByte(b & 0xFF);
+
+        assertEquals(ConnectionState.CONNECTED_TN3270E, fsm.getConnectionState());
+        assertTrue(fsm.isTn3270eBound());
+        connection.sentData.clear();
+
+        // Lock keyboard as if host app is waiting
+        inputProcessor.setKeyboardLocked(true);
+        assertTrue(inputProcessor.isKeyboardLocked());
+
+        // 1. User presses SYSREQ key (AID 0xF0)
+        inputProcessor.sendAid(DS3270Constants.AID_SYSREQ);
+
+        // Keyboard should now be unlocked and IAC AO (0xFF 0xF5) sent out-of-band
+        assertFalse(inputProcessor.isKeyboardLocked(), "Keyboard should be unlocked on SYSREQ");
+        boolean foundIacAo = false;
+        for (byte[] pkt : connection.sentData) {
+            if (pkt.length == 2 && (pkt[0] & 0xFF) == IAC && (pkt[1] & 0xFF) == AO) {
+                foundIacAo = true;
+            }
+        }
+        assertTrue(foundIacAo, "Expected raw IAC AO out-of-band telnet command");
+        assertEquals(ConnectionState.CONNECTED_SSCP, fsm.getConnectionState(), "Session should switch to CONNECTED_SSCP");
+        connection.sentData.clear();
+
+        // 2. User types in SSCP-LU mode (e.g. "LOGOFF") and presses Enter
+        inputProcessor.typeCharacter('L');
+        inputProcessor.typeCharacter('O');
+        inputProcessor.typeCharacter('G');
+        inputProcessor.typeCharacter('O');
+        inputProcessor.typeCharacter('F');
+        inputProcessor.typeCharacter('F');
+        inputProcessor.sendAid(DS3270Constants.AID_ENTER);
+
+        // Verify sent record has header DT_SSCP_LU_DATA (0x07)
+        assertEquals(1, connection.sentData.size(), "SSCP-LU input should produce one record");
+        byte[] sscpPkt = connection.sentData.get(0);
+        assertEquals(DT_SSCP_LU_DATA, sscpPkt[0] & 0xFF, "Data type should be DT_SSCP_LU_DATA (0x07)");
+        assertEquals(translator.unicodeToEbcdic('L'), sscpPkt[5] & 0xFF);
+        assertEquals(translator.unicodeToEbcdic('O'), sscpPkt[6] & 0xFF);
+        connection.sentData.clear();
+
+        // 3. Host sends inbound SSCP-LU unformatted prompt
+        ByteArrayOutputStream ussPrompt = new ByteArrayOutputStream();
+        ussPrompt.write(DT_SSCP_LU_DATA);
+        ussPrompt.write(0); ussPrompt.write(0); ussPrompt.write(0); ussPrompt.write(2);
+        ussPrompt.write(translator.unicodeToEbcdic('U'));
+        ussPrompt.write(translator.unicodeToEbcdic('S'));
+        ussPrompt.write(translator.unicodeToEbcdic('S'));
+        ussPrompt.write(IAC);
+        ussPrompt.write(EOR);
+        for (byte b : ussPrompt.toByteArray()) fsm.feedByte(b & 0xFF);
+
+        assertEquals('U', translator.ebcdicToUnicode(screenBuffer.getCellEC(80)));
+        assertEquals('S', translator.ebcdicToUnicode(screenBuffer.getCellEC(81)));
+        assertEquals('S', translator.ebcdicToUnicode(screenBuffer.getCellEC(82)));
+
+        // 4. User presses SYSREQ again to toggle back to 3270 session
+        inputProcessor.sendAid(DS3270Constants.AID_SYSREQ);
+        assertEquals(ConnectionState.CONNECTED_TN3270E, fsm.getConnectionState(), "Second SYSREQ should toggle back to CONNECTED_TN3270E");
+    }
+
+    @Test
+    public void testTn3270eResponseSignalingErrorResponse() {
+        config.setTn3270eEnabled(true);
+        fsm.onConnected();
+
+        feedBytes(IAC, DO, TELOPT_TN3270E);
+        feedBytes(IAC, SB, TELOPT_TN3270E, OP_SEND, OP_DEVICE_TYPE, IAC, SE);
+        byte[] devTypeIs = new byte[]{
+            (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E,
+            0x02, 0x04, 'I', 'B', 'M', '-', '3', '2', '7', '9', '-', '4', '-', 'E',
+            (byte) IAC, (byte) SE
+        };
+        for (byte b : devTypeIs) fsm.feedByte(b & 0xFF);
+
+        byte[] funcsReq = new byte[]{
+            (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E,
+            (byte) OP_FUNCTIONS, (byte) OP_REQUEST,
+            (byte) FUNC_BIND_IMAGE, (byte) FUNC_RESPONSES,
+            (byte) IAC, (byte) SE
+        };
+        for (byte b : funcsReq) fsm.feedByte(b & 0xFF);
+
+        // Bind session
+        byte[] bindPacket = new byte[EH_SIZE + 35];
+        bindPacket[0] = DT_BIND_IMAGE;
+        bindPacket[1] = 0; bindPacket[2] = 0; bindPacket[3] = 0; bindPacket[4] = 1;
+        bindPacket[EH_SIZE + 24] = 0x02;
+        ByteArrayOutputStream bStream = new ByteArrayOutputStream();
+        bStream.write(bindPacket, 0, bindPacket.length);
+        bStream.write(IAC);
+        bStream.write(EOR);
+        for (byte b : bStream.toByteArray()) fsm.feedByte(b & 0xFF);
+        connection.sentData.clear();
+
+        // Send a malformed 3270 record that triggers an error with ERROR_RESPONSE (0x01)
+        int seq = 0x0077;
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        bos.write(DT_3270_DATA);
+        bos.write(0x00);
+        bos.write(RSF_ERROR_RESPONSE); // 0x01
+        bos.write((seq >> 8) & 0xFF);
+        bos.write(seq & 0xFF);
+        bos.write(0xF5); // EraseWrite
+        // Truncated SBA order without address bytes to trigger an exception in dsProcessor
+        bos.write(0x11); // SBA without address bytes
+        bos.write(IAC);
+        bos.write(EOR);
+
+        // Note: dsProcessor gracefully handles or if it throws, negative response is sent.
+        // Let's verify what happens when exception or normal:
+        for (byte b : bos.toByteArray()) fsm.feedByte(b & 0xFF);
+    }
+}

lib3270j/src/test/java/haus/nightmare/lib3270j/telnet/TelnetFSMPhase2Test.java

@@ -153,9 +153,12 @@ public class TelnetFSMPhase2Test {
         fsm.onConnected();
         output.reset();
 
-        // Server sends DO TN3270E -> client sends WILL TN3270E and requests "LU_A"
+        // Server sends DO TN3270E -> client sends WILL TN3270E
         fsm.feedBytes(new byte[] { (byte) IAC, (byte) DO, (byte) TELOPT_TN3270E }, 0, 3);
 
+        // Server sends SB TN3270E SEND DEVICE-TYPE -> client requests "LU_A"
+        fsm.feedBytes(new byte[] { (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E, (byte) OP_SEND, (byte) OP_DEVICE_TYPE, (byte) IAC, (byte) SE }, 0, 7);
+
         String sent1 = new String(output.toByteArray());
         assertTrue(sent1.contains("LU_A"));
         output.reset();