diff --git a/openbsc/include/openbsc/mgcp.h b/openbsc/include/openbsc/mgcp.h
index 37194be..c60a455 100644
--- a/openbsc/include/openbsc/mgcp.h
+++ b/openbsc/include/openbsc/mgcp.h
@@ -119,5 +119,13 @@
 struct msgb *mgcp_handle_message(struct mgcp_config *cfg, struct msgb *msg);
 struct msgb *mgcp_create_response_with_data(int code, const char *msg, const char *trans, const char *data);
 
+/* adc helper */
+static inline int mgcp_timeslot_to_endpoint(int multiplex, int timeslot)
+{
+	if (timeslot == 0)
+		timeslot = 1;
+	return timeslot + (31 * multiplex);
+}
+
 
 #endif