diff --git a/bts/BTS_Tests_LAPDm.ttcn b/bts/BTS_Tests_LAPDm.ttcn
index da78ccb..4d4a988 100644
--- a/bts/BTS_Tests_LAPDm.ttcn
+++ b/bts/BTS_Tests_LAPDm.ttcn
@@ -813,11 +813,16 @@
 	f_testmatrix_each_chan(pars, refers(f_TC_nr_seq_error));
 }
 
-private function f_TC_rec_invalid_frame_txrx(integer sapi, LapdmFrame x) runs on ConnHdlr {
+private function f_TC_rec_invalid_frame_txrx(integer sapi, LapdmFrame x, integer line_nr) runs on ConnHdlr {
 	LAPDM.send(t_PH_DATA(0, false, x));
 	f_sleep(2.0); // T200
 	LAPDM.send(t_PH_DATA(0, false, ts_LAPDm_RR(sapi, c_r:=cr_MO_CMD, p:=true, nr:=0)));
-	LAPDM.receive(t_PH_DATA(0, false, tr_LAPDm_RR(sapi, c_r:=cr_MT_RSP, p:=true , nr := 0)));
+	timer T1 := 2.0;
+	T1.start;
+	alt {
+	[] LAPDM.receive(t_PH_DATA(0, false, tr_LAPDm_RR(sapi, c_r:=cr_MT_RSP, p:=true , nr := 0))) { T1.stop; }
+	[] T1.timeout{ Misc_Helpers.f_shutdown(__BFILE__, line_nr, fail, "Missing LAPDm_RR RSP"); }
+	}
 }
 
 /* 25.2.7     Test on receipt of invalid frames
@@ -842,84 +847,90 @@
 
 	/* MO Establish Request via LADPm: SAPI = 0, C = 0, P = 1, M = 0, 0 ≤ L ≤ N201.. */
 	LAPDM.send(t_PH_DATA(0, false, ts_LAPDm_SABM(sapi, c_r:=cr_MO_CMD, p:=true, l3:=l3_mo)));
-	RSL.receive(tr_RSL_EST_IND(g_chan_nr, link_id, l3_mo));
+	T.start
+	alt {
+	[] RSL.receive(tr_RSL_EST_IND(g_chan_nr, link_id, l3_mo)) {}
+	[] T.timeout{ Misc_Helpers.f_shutdown(__BFILE__, __LINE__, fail, "Missing RSL EST IND"); }
+	}
+	alt {
 	/* UA: SAPI = 0, R = 0, F = 1, M = 0, L = L of SABM. */
-	LAPDM.receive(t_PH_DATA(0, false, tr_LAPDm_UA(sapi, cr_MT_RSP, f:=true, l3:=l3_mo)));
-
+	[] LAPDM.receive(t_PH_DATA(0, false, tr_LAPDm_UA(sapi, cr_MT_RSP, f:=true, l3:=l3_mo))) { T.stop; }
+	[] T.timeout{ Misc_Helpers.f_shutdown(__BFILE__, __LINE__, fail, "Missing LAPDm UA RSP"); }
+	}
 
 	/* 1: One RR frame: SAPI = 0, R = 0, F = 0, M = 0, L > 0, N(R) = 1.
 	RR frame with the Length indicator greater than zero and a faulty N(R); */
 	var LapdmFrame x:= valueof(ts_LAPDm_RR(sapi, c_r:=cr_MO_CMD, p:=false, nr:=1));
 	x.ab.payload := f_rnd_octstring(5);
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 	/* 3: One REJ frame: SAPI = 0, R = 0, F = 0, M = 0, L = 0, N(R) = 1, EA = 0.
 	EJ frame with the EA bit set to zero and a faulty N(R); */
 	x:= valueof(ts_LAPDm_REJ(sapi, c_r:=cr_MO_CMD, p:=false, nr:=1));
 	x.ab.addr.ea := false;
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 	/* 4: One SABM frame: SAPI = 0, C = 1, P = 1, M = 0, L = 0, EL = 0.
 	SABM frame with the EL bit set to zero; */
 	l3_mo := ''O;
 	x:= valueof(ts_LAPDm_SABM(sapi, c_r:=cr_MO_CMD, p:=true, l3:=l3_mo));
 	x.ab.el := 0;
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 	/* 5: One DM frame: SAPI = 0, R = 0, F = 1, M = 0, L > 0.
 	DM frame with the Length indicator greater than zero;*/
 	x:= valueof(ts_LAPDm_DM(sapi, c_r:=cr_MO_CMD, f:=true));
 	x.ab.payload := f_rnd_octstring(5);
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 	/* 6: One DISC frame: SAPI = 0, C = 1, P = 1, M = 1, L = 0.
 	DISC frame with the M bit set to 1; */
 	x:= valueof(ts_LAPDm_DISC(sapi, c_r:=cr_MO_CMD, p:=true));
 	x.ab.m := true;
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 	/* 7: One UA frame: SAPI = 0, R = 0, F = 0, M = 0, L = 0, EA = 0.
 	UA frame with the EA bit set to zero*/
 	x:= valueof(ts_LAPDm_UA(sapi, c_r:=cr_MO_CMD, f:=false, l3:=''O));
 	x.ab.addr.ea := false;
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 	/* 8: One I frame: SAPI = 0, C = 1, P = 0, M = 0, L > N201, N(R) = 0, N(S) = 6.
 	I frame with the Length indicator greater than N201;*/
 	x:= valueof(ts_LAPDm_I(sapi, c_r:=cr_MO_CMD, p:=true, nr := 0, ns := 6, l3 := f_rnd_octstring(25)))
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 	/* 9: One I frame: SAPI = 0, C = 1, P = 0, M = 1, L < N201, N(R) = 0, N(S) = 7.
 	I frame with the M bit set to 1 and the Length indicator less than N201;*/
 	x:= valueof(ts_LAPDm_I(sapi, c_r:=cr_MO_CMD, p:=true, nr := 0, ns := 7, l3 := f_rnd_octstring(5)))
 	x.ab.m := true;
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 	/* 10: One RR frame: SAPI = 0, C = 1, P = 1, M = 0, L = 0, N(R) = 0. */
 	x:= valueof(ts_LAPDm_RR(sapi, c_r:=cr_MO_CMD, p:=true, nr:=0));
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 
 	/* command frames with correct Address and Length indicator field and a non-implemented control field */
 	/* 12: One command frame with Control Field = xxx1 1101. */
 	x:= valueof(ts_LAPDm_RR(sapi, c_r:=cr_MO_CMD, p:=false, nr:=1));
 	x.ab.ctrl.other := bit2int('00011101'B);
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 	/* 13: One command frame with Control field = xxx1 1011. */
 	x:= valueof(ts_LAPDm_RR(sapi, c_r:=cr_MO_CMD, p:=false, nr:=1));
 	x.ab.ctrl.other := bit2int('00011011'B);
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 	/* 14: One command frame with Control field = xxx1 0111. */
 	x:= valueof(ts_LAPDm_RR(sapi, c_r:=cr_MO_CMD, p:=false, nr:=1));
 	x.ab.ctrl.other := bit2int('00010001'B);
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 	/* 15: One command frame with Control field = 01x1 1111. */
 	x:= valueof(ts_LAPDm_RR(sapi, c_r:=cr_MO_CMD, p:=false, nr:=1));
 	x.ab.ctrl.other := bit2int('01011111'B);
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 	/* 16: One command frame with Control field = 1xx1 1111. */
 	x:= valueof(ts_LAPDm_RR(sapi, c_r:=cr_MO_CMD, p:=false, nr:=1));
 	x.ab.ctrl.other := bit2int('10011111'B);
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 	/* 17: One command frame with Control field = 0011 0011. */
 	x:= valueof(ts_LAPDm_RR(sapi, c_r:=cr_MO_CMD, p:=false, nr:=1));
 	x.ab.ctrl.other := bit2int('00110011'B);
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 	/* 18: One command frame with Control field = 1xx1 0011. */
 	x:= valueof(ts_LAPDm_RR(sapi, c_r:=cr_MO_CMD, p:=false, nr:=1));
 	x.ab.ctrl.other := bit2int('10010011'B);
-	f_TC_rec_invalid_frame_txrx(0, x);
+	f_TC_rec_invalid_frame_txrx(0, x, __LINE__);
 
 	deactivate(d);
 	fp_common_fini();