diff --git a/include/osmocom/gsm/gsm0808_utils.h b/include/osmocom/gsm/gsm0808_utils.h
index 097bd76..90ff677 100644
--- a/include/osmocom/gsm/gsm0808_utils.h
+++ b/include/osmocom/gsm/gsm0808_utils.h
@@ -77,6 +77,7 @@
 int gsm0808_cell_id_u_name(char *buf, size_t buflen,
 			   enum CELL_IDENT id_discr, const union gsm0808_cell_id_u *u);
 
+uint8_t gsm0808_enc_cause(struct msgb *msg, uint16_t cause);
 uint8_t gsm0808_enc_aoip_trasp_addr(struct msgb *msg,
 				    const struct sockaddr_storage *ss);
 int gsm0808_dec_aoip_trasp_addr(struct sockaddr_storage *ss,