diff --git a/include/osmocom/gsm/gsm_utils.h b/include/osmocom/gsm/gsm_utils.h
index cf63ea4..a572f50 100644
--- a/include/osmocom/gsm/gsm_utils.h
+++ b/include/osmocom/gsm/gsm_utils.h
@@ -59,6 +59,7 @@
 int gsm_7bit_decode(char *decoded, const uint8_t *user_data, uint8_t length);
 int gsm_7bit_decode_hdr(char *decoded, const uint8_t *user_data, uint8_t length, uint8_t ud_hdr_ind);
 int gsm_7bit_encode(uint8_t *result, const char *data);
+int gsm_7bit_encode_oct(uint8_t *result, const char *data, int *octets_written);
 
 /* the three functions below are helper functions and here for the unit test */
 int gsm_septets2octets(uint8_t *result, const uint8_t *rdata, uint8_t septet_len, uint8_t padding);