diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index 61fe1a7..82a54f3 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -3318,14 +3318,18 @@
 	var octetstring l2 := enc_LapdmFrame(valueof(l));
 	if (valueof(link_id.c) == SACCH) {
 		/* prepend dummy L1 header */
-		l2 := '0000'O & l2;
+		var L1ctlDataReq l1hl2 := {
+			l1header := valueof(ts_SacchL1Header(g_pars.l1_pars.ms_power_level, false, g_pars.l1_pars.ms_actual_ta)),
+			l2_payload := f_pad_oct(l2, 21, '2B'O)
+		}
+		L1CTL.send(ts_L1CTL_DATA_REQ_SACCH(g_chan_nr, link_id, l1hl2));
+	} else {
+		/* If required, pad L2 frame with constant 0x2b filling */
+		l2 := f_pad_oct(l2, 23, '2B'O);
+
+		log("encoding ", l, " to ", l2);
+		L1CTL.send(ts_L1CTL_DATA_REQ(g_chan_nr, link_id, l2));
 	}
-
-	/* If required, pad L2 frame with constant 0x2b filling */
-	l2 := f_pad_oct(l2, 23, '2B'O);
-
-	log("encoding ", l, " to ", l2);
-	L1CTL.send(ts_L1CTL_DATA_REQ(g_chan_nr, link_id, l2));
 }
 
 type record RllTestCase {