Index: asterisk-trunk/channels/chan_sip.c
===================================================================
--- asterisk-trunk.orig/channels/chan_sip.c	2009-07-30 12:54:09.000000000 +0300
+++ asterisk-trunk/channels/chan_sip.c	2009-07-30 12:55:51.000000000 +0300
@@ -8615,7 +8615,7 @@
 		p->jointcapability = ast_codec_choose(&p->prefs, p->jointcapability, 1);
 	}
 
-	if (p->jointcapability & AST_FORMAT_T140RED) {
+	if ((p->jointcapability & AST_FORMAT_T140RED) && p->trtp) {
 		p->red = 1;
 		ast_rtp_red_init(p->trtp, 300, red_data_pt, 2);
 	} else {