diff -urN asterisk-1.4.11.org/channels/chan_zap.c asterisk-1.4.11/channels/chan_zap.c
--- asterisk-1.4.11.org/channels/chan_zap.c	2007-08-17 23:01:43.000000000 +0200
+++ asterisk-1.4.11/channels/chan_zap.c	2007-10-06 06:09:46.353781463 +0200
@@ -137,7 +137,7 @@
  * is entirely unwilling to provide any assistance with their channel banks
  * even though their web site says they support their products for life.
  */
-/* #define ZHONE_HACK */
+#define ZHONE_HACK 1
 
 /*! \note
  * Define if you want to check the hook state for an FXO (FXS signalled) interface
@@ -3700,21 +3700,17 @@
 		ast_log(LOG_DEBUG, "Got event %s(%d) on channel %d (index %d)\n", event2str(res), res, p->channel, index);
 
 	if (res & (ZT_EVENT_PULSEDIGIT | ZT_EVENT_DTMFUP)) {
-		p->pulsedial =  (res & ZT_EVENT_PULSEDIGIT) ? 1 : 0;
+		int pulse =  (res & ZT_EVENT_PULSEDIGIT) ? 1 : 0;
 
-		ast_log(LOG_DEBUG, "Detected %sdigit '%c'\n", p->pulsedial ? "pulse ": "", res & 0xff);
-#ifdef HAVE_PRI
-		if (!p->proceeding && p->sig == SIG_PRI && p->pri && p->pri->overlapdial) {
-			/* absorb event */
-		} else {
-#endif
-			p->subs[index].f.frametype = AST_FRAME_DTMF_END;
-			p->subs[index].f.subclass = res & 0xff;
-#ifdef HAVE_PRI
+		ast_log(LOG_DEBUG, "Detected %sdigit '%c'\n", pulse ? "pulse ": "", res & 0xff);
+
+		if (res & 0xff != 1) {
+			/* try to reset zhone */
+			zt_set_hook(p->subs[SUB_REAL].zfd, ZT_OFFHOOK);
+			usleep(10);
+			zt_set_hook(p->subs[SUB_REAL].zfd, ZT_ONHOOK);
 		}
-#endif
-		zt_handle_dtmfup(ast, index, &f);
-		return f;
+		/* do nothing */
 	}
 
 	if (res & ZT_EVENT_DTMFDOWN) {