diff --git a/library/MNCC_Types.ttcn b/library/MNCC_Types.ttcn
index 258db3f..bc7c4e6 100644
--- a/library/MNCC_Types.ttcn
+++ b/library/MNCC_Types.ttcn
@@ -303,7 +303,7 @@
 };
 
 type int MNCC_notify (0..127);
-type int MNCC_keypad (0..127);
+type charstring MNCC_keypad length (1);
 
 type enumerated MNCC_bcap {
 	GSM_MNCC_BCAP_SPEECH	(0),