diff --git a/makefile b/makefile
index 91f46c2b..8c2d5930 100644
--- a/makefile
+++ b/makefile
@@ -1175,6 +1175,9 @@ ifneq (3,$(GCC_MAJOR_VERSION))
   ifneq (,$(findstring -Wunused-result,$(shell $(GCC_WARNINGS_CMD))))
     CFLAGS_O += -Wno-unused-result
   endif
+  ifneq (,$(findstring -Wformat-truncation,$(shell $(GCC_WARNINGS_CMD))))
+    CFLAGS_O += -Wno-format-truncation
+  endif
 endif
 ifneq (clean,$(MAKECMDGOALS))
   BUILD_FEATURES := $(BUILD_FEATURES). $(COMPILER_NAME)
diff --git a/sim_tmxr.c b/sim_tmxr.c
index bbd70622..e81515cc 100644
--- a/sim_tmxr.c
+++ b/sim_tmxr.c
@@ -1005,6 +1005,7 @@ char *address;
 char msg[512];
 uint32 poll_time = sim_os_msec ();
 
+memset (msg, 0, sizeof (msg));
 if (mp->last_poll_time == 0) {                          /* first poll initializations */
     UNIT *uptr = mp->uptr;
 
@@ -1063,7 +1064,7 @@ if (mp->master) {
         newsock = sim_accept_conn_ex (mp->master, &address, (mp->packet ? SIM_SOCK_OPT_NODELAY : 0));/* poll connect */
 
     if (newsock != INVALID_SOCKET) {                    /* got a live one? */
-        sprintf (msg, "tmxr_poll_conn() - Connection from %s", address);
+        snprintf (msg, sizeof (msg) - 1, "tmxr_poll_conn() - Connection from %s", address);
         tmxr_debug_connect (mp, msg);
         op = mp->lnorder;                               /* get line connection order list pointer */
         i = mp->lines;                                  /* play it safe in case lines == 0 */
@@ -1199,7 +1200,7 @@ for (i = 0; i < mp->lines; i++) {                       /* check each line in se
                             strcpy (lp->ipad, lp->destination);
                             lp->cnms = sim_os_msec ();
                             sim_getnames_sock (lp->sock, &sockname, &peername);
-                            sprintf (msg, "tmxr_poll_conn() - Outgoing Line Connection to %s (%s->%s) established", lp->destination, sockname, peername);
+                            snprintf (msg, sizeof (msg) -1, "tmxr_poll_conn() - Outgoing Line Connection to %s (%s->%s) established", lp->destination, sockname, peername);
                             tmxr_debug_connect_line (lp, msg);
                             free (sockname);
                             free (peername);
@@ -1211,7 +1212,7 @@ for (i = 0; i < mp->lines; i++) {                       /* check each line in se
                                 }
                             return i;
                         case -1:                                /* failed connection */
-                            sprintf (msg, "tmxr_poll_conn() - Outgoing Line Connection to %s failed", lp->destination);
+                            snprintf (msg, sizeof (msg) -1, "tmxr_poll_conn() - Outgoing Line Connection to %s failed", lp->destination);
                             tmxr_debug_connect_line (lp, msg);
                             tmxr_reset_ln (lp);                 /* retry */
                             break;
@@ -1224,7 +1225,7 @@ for (i = 0; i < mp->lines; i++) {                       /* check each line in se
                         char *sockname, *peername;
 
                         sim_getnames_sock (newsock, &sockname, &peername);
-                        sprintf (msg, "tmxr_poll_conn() - Incoming Line Connection from %s (%s->%s)", address, peername, sockname);
+                        snprintf (msg, sizeof (msg) -1, "tmxr_poll_conn() - Incoming Line Connection from %s (%s->%s)", address, peername, sockname);
                         tmxr_debug_connect_line (lp, msg);
                         free (sockname);
                         free (peername);
@@ -1235,14 +1236,14 @@ for (i = 0; i < mp->lines; i++) {                       /* check each line in se
 
                             if (sim_parse_addr (lp->destination, host, sizeof(host), NULL, NULL, 0, NULL, address)) {
                                 tmxr_msg (newsock, "Rejecting connection from unexpected source\r\n");
-                                sprintf (msg, "tmxr_poll_conn() - Rejecting line connection from: %s, Expected: %s", address, host);
+                                snprintf (msg, sizeof (msg) -1, "tmxr_poll_conn() - Rejecting line connection from: %s, Expected: %s", address, host);
                                 tmxr_debug_connect_line (lp, msg);
                                 sim_close_sock (newsock);
                                 free (address);
                                 continue;                           /* Try for another connection */
                                 }
                             if (lp->connecting) {
-                                sprintf (msg, "tmxr_poll_conn() - aborting outgoing line connection attempt to: %s", lp->destination);
+                                snprintf (msg, sizeof (msg) -1, "tmxr_poll_conn() - aborting outgoing line connection attempt to: %s", lp->destination);
                                 tmxr_debug_connect_line (lp, msg);
                                 sim_close_sock (lp->connecting);    /* abort our as yet unconnnected socket */
                                 lp->connecting = 0;
@@ -1286,7 +1287,7 @@ for (i = 0; i < mp->lines; i++) {                       /* check each line in se
 
     if (lp->destination && (!lp->sock) && (!lp->connecting) && (!lp->serport) && 
         (!lp->modem_control || (lp->modembits & TMXR_MDM_DTR))) {
-        sprintf (msg, "tmxr_poll_conn() - establishing outgoing connection to: %s", lp->destination);
+        snprintf (msg, sizeof (msg) - 1, "tmxr_poll_conn() - establishing outgoing connection to: %s", lp->destination);
         tmxr_debug_connect_line (lp, msg);
         lp->connecting = sim_connect_sock_ex (lp->datagram ? lp->port : NULL, lp->destination, "localhost", NULL, (lp->datagram ? SIM_SOCK_OPT_DATAGRAM : 0) | (lp->mp->packet ? SIM_SOCK_OPT_NODELAY : 0));
         }