diff --git a/sim_console.c b/sim_console.c
index 9421571b..990d10f6 100644
--- a/sim_console.c
+++ b/sim_console.c
@@ -148,7 +148,9 @@ int setenv(const char *envname, const char *envval, int overwrite);
 /* Forward Declarations of Platform specific routines */
 
 static t_stat sim_os_poll_kbd (void);
+#if defined(SIM_ASYNCH_IO) && defined(SIM_ASYNCH_MUX)
 static t_bool sim_os_poll_kbd_ready (int ms_timeout);
+#endif
 static t_stat sim_os_putchar (int32 out);
 static t_stat sim_os_ttinit (void);
 static t_stat sim_os_ttrun (void);
@@ -178,6 +180,7 @@ static t_stat sim_set_delay (int32 flag, CONST char *cptr);
 
 int32 sim_int_char = 005;                               /* interrupt character */
 int32 sim_dbg_int_char = 0;                             /* SIGINT char under debugger */
+int32 sim_dbg_signal = 0;                               /* Enable SIGINT to debugger */
 static t_bool sigint_message_issued = FALSE;
 int32 sim_brk_char = 000;                               /* break character */
 int32 sim_tt_pchar = 0x00002780;
@@ -317,7 +320,6 @@ static CTAB set_con_tab[] = {
     { "WRU",     &sim_set_kmap, KMAP_WRU    | KMAP_NZ },
     { "BRK",     &sim_set_kmap, KMAP_BRK },
     { "DEL",     &sim_set_kmap, KMAP_DEL    | KMAP_NZ },
-    { "DBGINT",  &sim_set_kmap, KMAP_DBGINT | KMAP_NZ },
     { "PCHAR",   &sim_set_pchar, 0 },
     { "SPEED",   &sim_set_cons_speed, 0 },
     { "TELNET",  &sim_set_telnet, 0 },
@@ -334,6 +336,11 @@ static CTAB set_con_tab[] = {
     { "DELAY", &sim_set_delay, 0 },
     { "RESPONSE", &sim_set_response, 1 | CMD_WANTSTR },
     { "NORESPONSE", &sim_set_response, 0 },
+    { "DBGINT",  &sim_set_kmap, KMAP_DBGINT | KMAP_NZ },
+    { "DBGSIG", &sim_set_dbgsignal, 0 },
+    { "DBGSIGNAL", &sim_set_dbgsignal, 0 },
+    { "NODBGSIG", &sim_reset_dbgsignal, 0 },
+    { "NODBGSIGNAL", &sim_reset_dbgsignal, 0 },
     { NULL, NULL, 0 }
     };
 
@@ -352,7 +359,7 @@ static SHTAB show_con_tab[] = {
     { "WRU", &sim_show_kmap, KMAP_WRU },
     { "BRK", &sim_show_kmap, KMAP_BRK },
     { "DEL", &sim_show_kmap, KMAP_DEL },
-#if (defined(__GNUC__) && !defined(__OPTIMIZE__) && !defined(_WIN32))       /* Debug build? */
+#if !defined(_WIN32) && !defined(_WIN64) && !defined(VMS)
     { "DBGINT", &sim_show_kmap, KMAP_DBGINT },
 #endif
     { "PCHAR", &sim_show_pchar, 0 },
@@ -366,6 +373,7 @@ static SHTAB show_con_tab[] = {
     { "INPUT", &sim_show_cons_send_input, 0 },
     { "RESPONSE", &sim_show_cons_send_input, -1 },
     { "DELAY", &sim_show_cons_expect, -1 },
+    { "DBGSIGNAL", &sim_show_dbgsignal, 0 },
     { NULL, NULL, 0 }
     };
 
@@ -2192,7 +2200,7 @@ else
 if (isprint(kmap_char&0xFF))
     fprintf (st, " = '%c'\n", kmap_char&0xFF);
 else
-    if (kmap_char <= 26)
+    if (kmap_char <= 32)
         fprintf (st, " = ^%c\n", '@' + (kmap_char&0xFF));
     else
         if (kmap_char == 28)
@@ -2951,6 +2959,48 @@ fprintf (st, "Console Send processing:\n");
 return sim_show_send_input (st, &sim_con_send);
 }
 
+/* Enable console signal to debugger (for GNU C, Clang and not on Windows. */
+t_stat sim_set_dbgsignal (int32 flag, CONST char *cptr)
+{
+#if !defined(_WIN32) && !defined(_WIN64) && !defined(VMS)
+if (cptr != NULL && *cptr != '\0')
+    return SCPE_2FARG;
+
+sim_dbg_signal = TRUE;             /* Enable SIGINT to debugger */
+return sim_messagef(SCPE_OK, "SIGINT to debugger enabled.\n");
+#else
+return sim_messagef(SCPE_NOFNC, "Debugger interrupt not supported on this platform.\n");
+#endif
+}
+
+/* Turn off debugger signal */
+t_stat sim_reset_dbgsignal (int32 flag, CONST char *cptr)
+{
+#if !defined(_WIN32) && !defined(_WIN64) && !defined(VMS)
+if (cptr != NULL && *cptr != '\0') /* too many arguments? */
+    return SCPE_2MARG;
+
+sim_dbg_signal = FALSE;            /* Disable SIGINT to debugger */
+return sim_messagef(SCPE_OK, "SIGINT to debugger is disabled.\n");
+#else
+return sim_messagef(SCPE_NOFNC, "Debugger interrupt not supported on this platform.\n");
+#endif
+}
+
+t_stat sim_show_dbgsignal (FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, CONST char *cptr)
+{
+#if !defined(_WIN32) && !defined(_WIN64) && !defined(VMS)
+if (cptr != NULL && *cptr != '\0') /* too many arguments? */
+    return SCPE_2MARG;
+
+fprintf(st, "%s interrupts to the debugger.\n", sim_dbg_signal ? "Delivering" : "Not delivering");
+#else
+fprintf(st, "Debugger interrupt not supported.\n");
+#endif
+
+return SCPE_OK;
+}
+
 /* Poll for character */
 
 t_stat sim_poll_kbd (void)
@@ -3791,26 +3841,30 @@ static t_stat sim_os_ttrun (void)
 {
 sim_debug (DBG_TRC, &sim_con_telnet, "sim_os_ttrun() - BSDTTY\n");
 
-#if (defined(__GNUC__) && !defined(__OPTIMIZE__))       /* Debug build? */
-if (sim_dbg_int_char == 0)
-    sim_dbg_int_char = sim_int_char + 1;
-runtchars.t_intrc = sim_dbg_int_char;                   /* let debugger get SIGINT with next highest char */
-if (!sigint_message_issued) {
-    char sigint_name[8];
+if (sim_dbg_signal) {
+    if (sim_dbg_int_char == 0)
+        sim_dbg_int_char = sim_int_char + 1;            /* Set a reasonable default */
+    runtchars.t_intrc = sim_dbg_int_char;               /* let debugger get SIGINT with next highest char */
 
-    if (isprint(sim_dbg_int_char&0xFF))
-        sprintf(sigint_name, "'%c'", sim_dbg_int_char&0xFF);
-    else
-        if (sim_dbg_int_char <= 26)
-            sprintf(sigint_name, "^%c", '@' + (sim_dbg_int_char&0xFF));
+    if (!sigint_message_issued) {
+        char sigint_name[8];
+
+        if (isprint(sim_dbg_int_char&0xFF))
+            sprintf(sigint_name, "'%c'", sim_dbg_int_char&0xFF);
         else
-            sprintf(sigint_name, "'\\%03o'", sim_dbg_int_char&0xFF);
-    sigint_message_issued = TRUE;
-    sim_messagef (SCPE_OK, "SIGINT will be delivered to your debugger when the %s character is entered\n", sigint_name);
+            if (sim_dbg_int_char <= 32)
+                sprintf(sigint_name, "'^%c'", '@' + (sim_dbg_int_char&0xFF));
+            else
+                sprintf(sigint_name, "'\\%03o'", sim_dbg_int_char&0xFF);
+
+        sim_messagef (SCPE_OK, "SIGINT will be delivered to your debugger when the %s character is entered\n",
+                      sigint_name);
+
+        sigint_message_issued = TRUE;
+        }
     }
-#else
-runtchars.t_intrc = sim_int_char;                       /* in case changed */
-#endif
+else
+    runtchars.t_intrc = sim_int_char;                   /* in case changed */
 fcntl (0, F_SETFL, runfl);                              /* non-block mode */
 if (ioctl (0, TIOCSETP, &runtty) < 0)
     return SCPE_TTIERR;
@@ -3979,24 +4033,28 @@ runtty.c_cc[VINTR] = 0;                                 /* OS X doesn't deliver
 #else
 runtty.c_cc[VINTR] = sim_int_char;                      /* in case changed */
 #endif
-#if (defined(__GNUC__) && !defined(__OPTIMIZE__))       /* Debug build? */
-if (sim_dbg_int_char == 0)
-    sim_dbg_int_char = sim_int_char + 1;
-runtty.c_cc[VINTR] = sim_dbg_int_char;                  /* let debugger get SIGINT with next highest char */
-if (!sigint_message_issued) {
-    char sigint_name[8];
+if (sim_dbg_signal) {
+    if (sim_dbg_int_char == 0)
+        sim_dbg_int_char = sim_int_char + 1;            /* Set a reasonable default */
+    runtty.c_cc[VINTR] = sim_dbg_int_char;              /* let debugger get SIGINT with next highest char */
 
-    if (isprint(sim_dbg_int_char&0xFF))
-        sprintf(sigint_name, "'%c'", sim_dbg_int_char&0xFF);
-    else
-        if (sim_dbg_int_char <= 26)
-            sprintf(sigint_name, "^%c", '@' + (sim_dbg_int_char&0xFF));
+    if (!sigint_message_issued) {
+        char sigint_name[8];
+
+        if (isprint(sim_dbg_int_char&0xFF))
+            sprintf(sigint_name, "'%c'", sim_dbg_int_char&0xFF);
         else
-            sprintf(sigint_name, "'\\%03o'", sim_dbg_int_char&0xFF);
-    sigint_message_issued = TRUE;
-    sim_messagef (SCPE_OK, "SIGINT will be delivered to your debugger when the %s character is entered\n", sigint_name);
+            if (sim_dbg_int_char <= 32)
+                sprintf(sigint_name, "'^%c'", '@' + (sim_dbg_int_char&0xFF));
+            else
+                sprintf(sigint_name, "'\\%03o'", sim_dbg_int_char&0xFF);
+
+        sim_messagef (SCPE_OK, "SIGINT will be delivered to your debugger when the %s character is entered\n",
+                      sigint_name);
+
+        sigint_message_issued = TRUE;
+        }
     }
-#endif
 if (tcsetattr (fileno(stdin), TCSETATTR_ACTION, &runtty) < 0)
     return SCPE_TTIERR;
 sim_os_set_thread_priority (PRIORITY_BELOW_NORMAL);     /* try to lower pri */
diff --git a/sim_console.h b/sim_console.h
index e044bf35..f413257d 100644
--- a/sim_console.h
+++ b/sim_console.h
@@ -94,6 +94,8 @@ t_stat sim_set_cons_expect (int32 flg, CONST char *cptr);
 t_stat sim_set_cons_noexpect (int32 flg, CONST char *cptr);
 t_stat sim_set_pchar (int32 flag, CONST char *cptr);
 t_stat sim_set_cons_speed (int32 flag, CONST char *cptr);
+t_stat sim_set_dbgsignal (int32 flag, CONST char *cptr);
+t_stat sim_reset_dbgsignal (int32 flag, CONST char *cptr);
 t_stat sim_show_console (FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, CONST char *cptr);
 t_stat sim_show_remote_console (FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, CONST char *cptr);
 t_stat sim_show_kmap (FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, CONST char *cptr);
@@ -106,6 +108,7 @@ t_stat sim_show_cons_buff (FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, CONST
 t_stat sim_show_cons_log (FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, CONST char *cptr);
 t_stat sim_show_cons_debug (FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, CONST char *cptr);
 t_stat sim_show_cons_expect (FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, CONST char *cptr);
+t_stat sim_show_dbgsignal (FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, CONST char *cptr);
 t_stat sim_check_console (int32 sec);
 t_stat sim_open_logfile (const char *filename, t_bool binary, FILE **pf, FILEREF **pref);
 t_stat sim_close_logfile (FILEREF **pref);