diff --git a/openbsc/src/libmsc/gsm_04_80.c b/openbsc/src/libmsc/gsm_04_80.c
index 39738a5..b30f9ee 100644
--- a/openbsc/src/libmsc/gsm_04_80.c
+++ b/openbsc/src/libmsc/gsm_04_80.c
@@ -72,7 +72,7 @@
 
 	/* First put the payload text into the message */
 	ptr8 = msgb_put(msg, 0);
-	response_len = gsm_7bit_encode(ptr8, response_text);
+	gsm_7bit_encode_n_ussd(ptr8, msgb_tailroom(msg), response_text, &response_len);
 	msgb_put(msg, response_len);
 
 	/* Then wrap it as an Octet String */