diff --git a/src/libmsc/ran_msg_iu.c b/src/libmsc/ran_msg_iu.c
index c10df4d..ee1d0a5 100644
--- a/src/libmsc/ran_msg_iu.c
+++ b/src/libmsc/ran_msg_iu.c
@@ -153,7 +153,8 @@
 		.msg_type = RAN_MSG_ASSIGNMENT_COMPLETE,
 		.msg_name = "RANAP RAB Assignment Response",
 		.assignment_complete = {
-			.codec = CODEC_AMR_8000_1,
+			.codec_present = true,
+			.codec = CODEC_IUFP,
 		},
 	};
 	if (osmo_sockaddr_str_from_str(&ran_dec_msg->assignment_complete.remote_rtp, addr, port)) {