From a3c52e081791ac168cf051c051b82f26214b7632 Mon Sep 17 00:00:00 2001
From: Scott Duensing <scott@duensing.com>
Date: Thu, 26 Feb 2026 00:06:39 -0600
Subject: [PATCH] Add terminal query responses for BBS ANSI detection

Handle ENQ (0x05), ESC[c (Device Attributes), ESC[5n (Device Status
Report), and ESC[6n (Cursor Position Report).  Responses are sent
back through OnKeyData so BBSes can detect ANSI terminal capability.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 delphi/KPANSI.PAS | 27 +++++++++++++++++++++++++++
 delphi/README.md  |  4 ++++
 2 files changed, 31 insertions(+)

diff --git a/delphi/KPANSI.PAS b/delphi/KPANSI.PAS
index d6eae58..42fbd0b 100644
--- a/delphi/KPANSI.PAS
+++ b/delphi/KPANSI.PAS
@@ -639,6 +639,28 @@ begin
         FSaveCurRow := FCursorRow;
         FSaveCurCol := FCursorCol;
       end;
+    'c': { DA - Device Attributes }
+      begin
+        { Respond as VT100 with no options }
+        if Assigned(FOnKeyData) then
+          FOnKeyData(Self, #27'[?1;0c');
+      end;
+    'n': { DSR - Device Status Report }
+      begin
+        if P1 = 5 then
+        begin
+          { Terminal status: report OK }
+          if Assigned(FOnKeyData) then
+            FOnKeyData(Self, #27'[0n');
+        end
+        else if P1 = 6 then
+        begin
+          { Cursor Position Report: respond with ESC[row;colR (1-based) }
+          if Assigned(FOnKeyData) then
+            FOnKeyData(Self, #27'[' + IntToStr(FCursorRow + 1) + ';' +
+              IntToStr(FCursorCol + 1) + 'R');
+        end;
+      end;
     'u': { RCP - Restore Cursor Position }
       begin
         FCursorRow := FSaveCurRow;
@@ -1201,6 +1223,11 @@ begin
                 TabCol := FCols - 1;
               FCursorCol := TabCol;
             end;
+          #5: { ENQ - Answerback }
+            begin
+              if Assigned(FOnKeyData) then
+                FOnKeyData(Self, #27'[?1;0c');
+            end;
           #7: { BEL }
             MessageBeep(0);
           else
diff --git a/delphi/README.md b/delphi/README.md
index 70f58d2..4579b31 100644
--- a/delphi/README.md
+++ b/delphi/README.md
@@ -116,6 +116,9 @@ CSI (ESC\[) sequences:
 | ESC\[*params*m | SGR | Set graphic rendition (see below) |
 | ESC\[s | SCP | Save cursor position |
 | ESC\[u | RCP | Restore cursor position |
+| ESC\[c | DA | Device Attributes — responds ESC\[?1;0c (VT100) |
+| ESC\[5n | DSR | Device Status Report — responds ESC\[0n (OK) |
+| ESC\[6n | CPR | Cursor Position Report — responds ESC\[*row*;*col*R |
 
 SGR codes:
 
@@ -148,6 +151,7 @@ Control characters:
 | LF (#10) | Line feed (scrolls at bottom) |
 | BS (#8) | Backspace (no erase) |
 | TAB (#9) | Tab to next 8-column stop |
+| ENQ (#5) | Answerback — responds ESC\[?1;0c (VT100) |
 | BEL (#7) | System beep |
 
 **ANSI Music:**