diff --git a/remsim/RemsimClient_Tests.ttcn b/remsim/RemsimClient_Tests.ttcn
index d7d6bc7..219573c 100644
--- a/remsim/RemsimClient_Tests.ttcn
+++ b/remsim/RemsimClient_Tests.ttcn
@@ -299,8 +299,8 @@
 			integer count := 100, integer i := 0) runs on client_test_CT
 {
 	for (var integer j := 0; j < count; j := j+1) {
-		var octetstring c_apdu := f_rnd_octstring(f_rnd_int(270));
-		var octetstring r_apdu := f_rnd_octstring(f_rnd_int(270));
+		var octetstring c_apdu := f_rnd_octstring_rnd_len(270);
+		var octetstring r_apdu := f_rnd_octstring_rnd_len(270);
 		f_client2bank(cslot, bslot, c_apdu, i:=i);
 		f_bank2client(bslot, cslot, r_apdu, i:=i);
 	}
@@ -345,8 +345,8 @@
 
 	f_set_atr(cslot, '3B9F96801FC78031A073BE21136743200718000001A5'O, i:=1);
 
-	var octetstring c_apdu := f_rnd_octstring(f_rnd_int(270));
-	var octetstring r_apdu := f_rnd_octstring(f_rnd_int(270));
+	var octetstring c_apdu := f_rnd_octstring_rnd_len(270);
+	var octetstring r_apdu := f_rnd_octstring_rnd_len(270);
 	/* Send C-APDU from correct ClientId/Slot to simulated bankd */
 	f_client2bank(cslot, bslot, c_apdu, i:=1);
 	/* respond with R-APDU from correct bankId/Slot but stating wrong ClientId */
@@ -372,8 +372,8 @@
 
 	f_set_atr(cslot, '3B9F96801FC78031A073BE21136743200718000001A5'O, i:=1);
 
-	var octetstring c_apdu := f_rnd_octstring(f_rnd_int(270));
-	var octetstring r_apdu := f_rnd_octstring(f_rnd_int(270));
+	var octetstring c_apdu := f_rnd_octstring_rnd_len(270);
+	var octetstring r_apdu := f_rnd_octstring_rnd_len(270);
 	/* Send C-APDU from correct ClientId/Slot to simulated bankd */
 	f_client2bank(cslot, bslot, c_apdu, i:=1);
 	/* respond with R-APDU from wrong bankId but stating correct ClientId */