diff --git a/mgw/MGCP_Test.ttcn b/mgw/MGCP_Test.ttcn
index f6dfe57..c4f97a8 100644
--- a/mgw/MGCP_Test.ttcn
+++ b/mgw/MGCP_Test.ttcn
@@ -1693,7 +1693,7 @@
 
 	/* Create one connection in loopback mode, test if the RTP packets are
 	 * actually reflected */
-	testcase TC_one_crcx_loopback_rtp() runs on dummy_CT {
+	function f_TC_one_crcx_loopback_rtp(boolean one_phase := true) runs on dummy_CT {
 		var RtpFlowData flow;
 		var MgcpEndpoint ep := c_mgw_ep_rtpbridge & "1@" & c_mgw_domain;
 		var MgcpCallId call_id := '1225'H;
@@ -1702,7 +1702,7 @@
 		f_init(ep);
 		flow := valueof(t_RtpFlow(mp_local_ipv4, mp_remote_ipv4, 111, "GSM-HR-08/8000/1"));
 		flow.em.portnr := 10000;
-		f_flow_create(RTPEM[0], ep, call_id, "loopback", flow);
+		f_flow_create(RTPEM[0], ep, call_id, "loopback", flow, one_phase := one_phase);
 
 		f_rtpem_mode(RTPEM[0], RTPEM_MODE_BIDIR);
 		f_sleep(1.0);
@@ -1722,6 +1722,21 @@
 		setverdict(pass);
 	}
 
+	/* Create one connection in loopback mode, test if the RTP packets are
+	 * actually reflected */
+	testcase TC_one_crcx_loopback_rtp() runs on dummy_CT {
+		 f_TC_one_crcx_loopback_rtp(one_phase := true)
+	}
+
+	/* Same as above, but we will intenionally not tell the MGW where to
+	 * send the outgoing traffic. The connection is still created in
+	 * loopback mode, so the MGW should take the originating address from
+	 * the incoming RTP packet and send it back to the source */
+	testcase TC_one_crcx_loopback_rtp_implicit() runs on dummy_CT {
+		 f_TC_one_crcx_loopback_rtp(one_phase := false)
+	}
+
+
 	function f_TC_two_crcx_and_rtp(boolean bidir, charstring codec_name_a, integer pt_a,
 					charstring codec_name_b, integer pt_b) runs on dummy_CT {
 		var RtpFlowData flow[2];
@@ -2426,6 +2441,7 @@
 
 		execute(TC_one_crcx_receive_only_rtp());
 		execute(TC_one_crcx_loopback_rtp());
+		execute(TC_one_crcx_loopback_rtp_implicit());
 		execute(TC_two_crcx_and_rtp());
 		execute(TC_two_crcx_and_rtp_bidir());
 		execute(TC_two_crcx_diff_pt_and_rtp());