diff -urN asterisk-1.0.2.orig/channels/chan_iax2.c asterisk-1.0.2/channels/chan_iax2.c
--- asterisk-1.0.2.orig/channels/chan_iax2.c	2004-10-25 19:57:25.000000000 +0200
+++ asterisk-1.0.2/channels/chan_iax2.c	2004-10-27 20:37:09.948419048 +0200
@@ -7,6 +7,9 @@
  *
  * Mark Spencer <markster@digium.com>
  *
+ * Hangup cause signalling implementation by
+ * Levent Guendogdu <levon@feature-it.com>
+ *
  * This program is free software, distributed under the terms of
  * the GNU General Public License
  */
@@ -2397,14 +2400,19 @@
 static int iax2_hangup(struct ast_channel *c) 
 {
 	unsigned short callno = PTR_TO_CALLNO(c->pvt->pvt);
+	struct iax_ie_data ied;
+	char causestr[256];
+	sprintf(causestr, "%i", c->hangupcause);
 	int alreadygone;
 	ast_mutex_lock(&iaxsl[callno]);
 	if (callno && iaxs[callno]) {
-		ast_log(LOG_DEBUG, "We're hanging up %s now...\n", c->name);
+		memset(&ied, 0, sizeof(ied));
+		iax_ie_append_str(&ied, IAX_IE_CAUSE, causestr);
+		ast_log(LOG_DEBUG, "We're hanging up %s with cause %i now...\n", c->name, c->hangupcause);
 		alreadygone = iaxs[callno]->alreadygone;
 		/* Send the hangup unless we have had a transmission error or are already gone */
 		if (!iaxs[callno]->error && !alreadygone) 
-			send_command_final(iaxs[callno], AST_FRAME_IAX, IAX_COMMAND_HANGUP, 0, NULL, 0, -1);
+		        send_command_final(iaxs[callno], AST_FRAME_IAX, IAX_COMMAND_HANGUP, 0, ied.buf, ied.pos, -1);
 		/* Explicitly predestroy it */
 		iax2_predestroy_nolock(callno);
 		/* If we were already gone to begin with, destroy us now */
@@ -5487,6 +5495,11 @@
 			case IAX_COMMAND_HANGUP:
 				iaxs[fr.callno]->alreadygone = 1;
 				ast_log(LOG_DEBUG, "Immediately destroying %d, having received hangup\n", fr.callno);
+
+				/* Set hangup cause */
+				if (ies.cause)
+				  iaxs[fr.callno]->owner->hangupcause = atoi(ies.cause);
+
 				/* Send ack immediately, before we destroy */
 				send_command_immediate(iaxs[fr.callno], AST_FRAME_IAX, IAX_COMMAND_ACK, fr.ts, NULL, 0,fr.iseqno);
 				iax2_destroy_nolock(fr.callno);