diff --git a/openbsc/src/libmsc/gsm_04_11.c b/openbsc/src/libmsc/gsm_04_11.c
index e554b74..19b6030 100644
--- a/openbsc/src/libmsc/gsm_04_11.c
+++ b/openbsc/src/libmsc/gsm_04_11.c
@@ -106,7 +106,8 @@
 	sms->data_coding_scheme = dcs;
 	strncpy(sms->dst.addr, receiver->extension, sizeof(sms->dst.addr)-1);
 	/* Generate user_data */
-	sms->user_data_len = gsm_7bit_encode(sms->user_data, sms->text);
+	sms->user_data_len = gsm_7bit_encode_n(sms->user_data, sizeof(sms->user_data),
+						sms->text, NULL);
 
 	return sms;
 }