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) {
--- asterisk/channels/chan_zap.c.org	2007-09-26 09:08:42.423698383 +0200
+++ asterisk/channels/chan_zap.c	2007-09-26 09:09:43.422303554 +0200
@@ -1607,11 +1607,18 @@
 
 static inline int zt_set_hook(int fd, int hs)
 {
-	int x, res;
+	int x, res, count = 0;
 
 	x = hs;
 	res = ioctl(fd, ZT_HOOK, &x);
 
+	while (res < 0 && count < 20) {
+		usleep(100000); /* 1/10 sec. */
+		x = hs;
+		res = ioctl(fd, ZT_HOOK, &x);
+		count++;
+	}
+
 	if (res < 0) {
 		if (errno == EINPROGRESS)
 			return 0;