diff --git a/ns/NS_Tests.ttcn b/ns/NS_Tests.ttcn
index 8b321ff..58aeacd 100644
--- a/ns/NS_Tests.ttcn
+++ b/ns/NS_Tests.ttcn
@@ -200,7 +200,7 @@
  * TTCN <-  NS: status (cause blocked)
  */
 testcase TC_rx_block_unitdata_over_blocked() runs on RAW_Test_CT {
-	tx_block_by_vty();
+	f_tx_block_by_vty();
 	f_sleep(1.0);
 
 	NSCP[0].send(ts_NS_UNITDATA(t_SduCtrlB, 42, '0011234242230101'O));
@@ -301,7 +301,7 @@
  * TTCN <-  NS: block
  * TTCN  -> NS: block ack
  */
-function tx_block_by_vty(float guard_secs := 30.0) runs on RAW_Test_CT {
+function f_tx_block_by_vty(float guard_secs := 30.0) runs on RAW_Test_CT {
 	f_init_vty();
 	f_init_ns_codec(mp_nsconfig, guard_secs := guard_secs);
 
@@ -321,7 +321,7 @@
 }
 
 testcase TC_tx_block_by_vty() runs on RAW_Test_CT {
-	tx_block_by_vty(30.0);
+	f_tx_block_by_vty(30.0);
 	f_sleep(1.0);
 	f_clean_ns_codec();
 }
@@ -332,7 +332,7 @@
 testcase TC_tx_block_by_vty_reset() runs on RAW_Test_CT {
 	timer T := 10.0;
 
-	tx_block_by_vty(60.0);
+	f_tx_block_by_vty(60.0);
 	f_outgoing_ns_reset();
 
 	var default d := activate(ax_rx_fail_on_any_ns());