diff --git a/library/L1CTL_PortType.ttcn b/library/L1CTL_PortType.ttcn
index 7d69b46..19b3ee3 100644
--- a/library/L1CTL_PortType.ttcn
+++ b/library/L1CTL_PortType.ttcn
@@ -80,6 +80,20 @@
 		}
 	}
 
+	function f_L1CTL_TCH_MODE(L1CTL_PT pt, L1ctlTchMode tch_mode) {
+		timer T := 2.0;
+		pt.send(ts_L1CTL_TCH_MODE_REQ(tch_mode));
+		T.start;
+		alt {
+		[] pt.receive(tr_L1CTL_MsgType(L1CTL_TCH_MODE_CONF)) { }
+		[] pt.receive { repeat; }
+		[] T.timeout {
+			setverdict(fail, "Timeout waiting for L1CTL_TCH_MODE_CONF");
+			mtc.stop;
+			}
+		}
+	}
+
 	function f_L1CTL_RACH(L1CTL_PT pt, uint8_t ra, uint8_t combined := 1, uint16_t offset := 0,
 			      template (value) RslChannelNr chan_nr := ts_RslChanNr_RACH(0),
 			      template (value) RslLinkId link_id := ts_RslLinkID_DCCH(0))