diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index 0a19b3cb19..2c824f1641 100755
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -1864,18 +1864,31 @@ static int transmit_response_reliable(struct sip_pvt *p, char *msg, struct sip_r
 /*--- hangup_sip2cause: Convert SIP hangup causes to Asterisk hangup causes ---*/
 static int hangup_sip2cause(int cause)
 {
-/* Possible values from causes.h
-        AST_CAUSE_NOTDEFINED    AST_CAUSE_NORMAL        AST_CAUSE_BUSY
-        AST_CAUSE_FAILURE       AST_CAUSE_CONGESTION    AST_CAUSE_UNALLOCATED
-*/
+/* Possible values taken from causes.h */
 
 	switch(cause) {
+		case 403:       /* Not found */
+			return AST_CAUSE_CALL_REJECTED;
 		case 404:       /* Not found */
 			return AST_CAUSE_UNALLOCATED;
-		case 483:       /* Too many hops */
+		case 408:       /* No reaction */
+			return AST_CAUSE_NO_USER_RESPONSE;
+		case 480:       /* No answer */
 			return AST_CAUSE_FAILURE;
-		case 486:
+		case 483:       /* Too many hops */
+			return AST_CAUSE_NO_ANSWER;
+		case 486:	/* Busy everywhere */
 			return AST_CAUSE_BUSY;
+		case 488:	/* No codecs approved */
+			return AST_CAUSE_BEARERCAPABILITY_NOTAVAIL;
+		case 500:	/* Server internal failure */
+			return AST_CAUSE_FAILURE;
+		case 501:	/* Call rejected */
+			return AST_CAUSE_FACILITY_REJECTED;
+		case 502:	
+			return AST_CAUSE_DESTINATION_OUT_OF_ORDER;
+		case 503:	/* Service unavailable */
+			return AST_CAUSE_CONGESTION;
 		default:
 			return AST_CAUSE_NORMAL;
 	}
@@ -1883,24 +1896,85 @@ static int hangup_sip2cause(int cause)
 	return 0;
 }
 
+
 /*--- hangup_cause2sip: Convert Asterisk hangup causes to SIP codes ---*/
+/* Possible values from causes.h
+        AST_CAUSE_NOTDEFINED    AST_CAUSE_NORMAL        AST_CAUSE_BUSY
+        AST_CAUSE_FAILURE       AST_CAUSE_CONGESTION    AST_CAUSE_UNALLOCATED
+
+	In addition to these, a lot of PRI codes is defined in causes.h 
+	...should we take care of them too ?
+	
+	Quote RFC 3398
+
+   ISUP Cause value                        SIP response
+   ----------------                        ------------
+   1  unallocated number                   404 Not Found
+   2  no route to network                  404 Not found
+   3  no route to destination              404 Not found
+   16 normal call clearing                 --- (*)
+   17 user busy                            486 Busy here
+   18 no user responding                   408 Request Timeout
+   19 no answer from the user              480 Temporarily unavailable
+   20 subscriber absent                    480 Temporarily unavailable
+   21 call rejected                        403 Forbidden (+)
+   22 number changed (w/o diagnostic)      410 Gone
+   22 number changed (w/ diagnostic)       301 Moved Permanently
+   23 redirection to new destination       410 Gone
+   26 non-selected user clearing           404 Not Found (=)
+   27 destination out of order             502 Bad Gateway
+   28 address incomplete                   484 Address incomplete
+   29 facility rejected                    501 Not implemented
+   31 normal unspecified                   480 Temporarily unavailable
+*/
 static char *hangup_cause2sip(int cause)
 {
 	switch(cause)
 	{
+		case AST_CAUSE_UNALLOCATED:		/* 1 */
+		case AST_CAUSE_NO_ROUTE_DESTINATION:	/* 3 IAX2: Can't find extension in context */
+		case AST_CAUSE_NO_ROUTE_TRANSIT_NET:	/* 2 */
+			return "404 Not Found";
+                case AST_CAUSE_CONGESTION:		/* 34 */
+                case AST_CAUSE_SWITCH_CONGESTION:	/* 42 */
+                        return "503 Service Unavailable";
+		case AST_CAUSE_NO_USER_RESPONSE:	/* 18 */
+			return "408 Request Timeout";
+		case AST_CAUSE_NO_ANSWER:		/* 19 */
+			return "480 Temporarily unavailable";
+		case AST_CAUSE_CALL_REJECTED:		/* 21 */
+			return "403 Forbidden";
+		case AST_CAUSE_NUMBER_CHANGED:		/* 22 */
+			return "410 Gone";
+		case AST_CAUSE_NORMAL_UNSPECIFIED:	/* 31 */
+			return "480 Temporarily unavailable";
+		case AST_CAUSE_INVALID_NUMBER_FORMAT:
+			return "484 Address incomplete";
+		case AST_CAUSE_USER_BUSY:
+			return "486 Busy here";
 	   	case AST_CAUSE_FAILURE:
                         return "500 Server internal failure";
-                case AST_CAUSE_CONGESTION:
+		case AST_CAUSE_FACILITY_REJECTED:	/* 29 */
+			return "501 Not Implemented";
+		case AST_CAUSE_CHAN_NOT_IMPLEMENTED:
                         return "503 Service Unavailable";
-		case AST_CAUSE_BUSY:
-			return "486 Busy";
+		/* Used in chan_iax2 */
+		case AST_CAUSE_DESTINATION_OUT_OF_ORDER:
+                        return "502 Bad Gateway";
+		case AST_CAUSE_BEARERCAPABILITY_NOTAVAIL:	/* Can't find codec to connect to host */
+                        return "488 Not Acceptable Here";
+			
+		case AST_CAUSE_NOTDEFINED:
 		default:
+			ast_log(LOG_DEBUG, "AST hangup cause %d (no match found in SIP)\n", cause);
 			return NULL;
 	}
+
 	/* Never reached */
 	return 0;
 }
 
+
 /*--- sip_hangup: Hangup SIP call ---*/
 /* Part of PBX interface */
 static int sip_hangup(struct ast_channel *ast)