diff --git a/openbsc/src/libmsc/mncc_builtin.c b/openbsc/src/libmsc/mncc_builtin.c
index 5c3461b..7d5a7f1 100644
--- a/openbsc/src/libmsc/mncc_builtin.c
+++ b/openbsc/src/libmsc/mncc_builtin.c
@@ -65,16 +65,21 @@
 	return NULL;
 }
 
-static uint8_t determine_lchan_mode(struct gsm_mncc *setup)
+uint8_t mncc_codec_for_mode(int lchan_type)
 {
 	/* FIXME: check codec capabilities of the phone */
 
-	if (setup->lchan_type != GSM_LCHAN_TCH_H)
+	if (lchan_type != GSM_LCHAN_TCH_H)
 		return mncc_int.def_codec[0];
 	else
 		return mncc_int.def_codec[1];
 }
 
+static uint8_t determine_lchan_mode(struct gsm_mncc *setup)
+{
+	return mncc_codec_for_mode(setup->lchan_type);
+}
+
 /* on incoming call, look up database and send setup to remote subscr. */
 static int mncc_setup_ind(struct gsm_call *call, int msg_type,
 			  struct gsm_mncc *setup)