diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index 9503bec0b..89d1d2c1b 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -2099,6 +2099,25 @@ private function f_est_dchan(boolean encr_enable := false, RSL_IE_List more_ies
 		f_L1CTL_CRYPTO_REQ(L1CTL, g_pars.chan_nr, alg_id, g_pars.encr.key);
 	}
 
+	/* Send TCH Mode Request to the L1 if needed */
+	if (match(g_pars.chan_mode.spd_ind, (RSL_SPDI_SPEECH, RSL_SPDI_DATA))) {
+		var L1ctlTchMode tch_mode;
+
+		select (g_pars.chan_mode.coding_alg_rate) {
+		case (RSL_CMOD_NO_RESOURCE) { tch_mode := L1CTL_CHAN_MODE_SIGN; }
+		case (RSL_CMOD_SP_GSM1) { tch_mode := L1CTL_CHAN_MODE_SPEECH_V1; }
+		case (RSL_CMOD_SP_GSM2) { tch_mode := L1CTL_CHAN_MODE_SPEECH_V2; }
+		case (RSL_CMOD_SP_GSM3) { tch_mode := L1CTL_CHAN_MODE_SPEECH_V3; }
+		case else {
+			log("RSL channel mode := ", g_pars.chan_mode.coding_alg_rate,
+			    " is not supported by the L1, falling back to signalling");
+			tch_mode := L1CTL_CHAN_MODE_SIGN;
+			}
+		}
+
+		f_L1CTL_TCH_MODE(L1CTL, tch_mode);
+	}
+
 	g_first_meas_res := true;
 }
 
diff --git a/library/L1CTL_PortType.ttcn b/library/L1CTL_PortType.ttcn
index 7d69b4665..19b3ee39e 100644
--- a/library/L1CTL_PortType.ttcn
+++ b/library/L1CTL_PortType.ttcn
@@ -80,6 +80,20 @@ module L1CTL_PortType {
 		}
 	}
 
+	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))