diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index b793742b10..2c8370be5d 100644
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -17934,7 +17934,6 @@ static void handle_response_invite(struct sip_pvt *p, int resp, const char *rest
 	case 183:	/* Session progress */
 		if (!req->ignore && (p->invitestate != INV_CANCELLED) && sip_cancel_destroy(p))
 			ast_log(LOG_WARNING, "Unable to cancel SIP destruction.  Expect bad things.\n");
-		/* Ignore 183 Session progress without SDP */
 		if (!req->ignore && p->owner) {
 			if (get_rpid(p, req)) {
 				/* Queue a connected line update */
@@ -17954,6 +17953,18 @@ static void handle_response_invite(struct sip_pvt *p, int resp, const char *rest
 				/* Queue a progress frame */
 				ast_queue_control(p->owner, AST_CONTROL_PROGRESS);
 			}
+		} else {
+			/* Alcatel PBXs are known to send 183s with no SDP after sending
+			 * a 100 Trying response. We're just going to treat this sort of thing
+			 * the same as we would treat a 180 Ringing
+			 */
+			/*XXX I'm just following the same procedure for a 180 response, which
+			 * doesn't change the invitestate of p. Shouldn't it be INV_PROCEEDING
+			 * though?
+			 */
+			if (!req->ignore && p->owner) {
+				ast_queue_control(p->owner, AST_CONTROL_RINGING);
+			}
 		}
 		check_pendings(p);
 		break;