diff --git a/library/RAN_Emulation.ttcnpp b/library/RAN_Emulation.ttcnpp
index 843cc9e..9a65eb7 100644
--- a/library/RAN_Emulation.ttcnpp
+++ b/library/RAN_Emulation.ttcnpp
@@ -585,7 +585,7 @@
 			}
 		}
 		client := f_imsi_table_find(oct2hex(imsi), tmsi);
-		if (isvalue(client)) {
+		if (client != null) {
 			log("CommonRanapUnitdataCallback: IMSI/TMSI found in table, dispatching to ",
 				client);
 			CLIENT.send(ranap) to client;