diff --git a/library/SCCP_Templates.ttcn b/library/SCCP_Templates.ttcn
index b0e6df7..ff4d745 100644
--- a/library/SCCP_Templates.ttcn
+++ b/library/SCCP_Templates.ttcn
@@ -143,7 +143,7 @@
 		calledPAddress := ConvertASPAddressToEncodedAddress_itu(called),
 		callingPAddress := ConvertASPAddressToEncodedAddress_itu(calling),
 		data := {
-			paramLength := lengthof(data),
+			paramLength := ?,
 			data := data
 		}
 	}