diff --git a/library/RTP_Emulation.ttcn b/library/RTP_Emulation.ttcn
index 2494d74..7b9be68 100644
--- a/library/RTP_Emulation.ttcn
+++ b/library/RTP_Emulation.ttcn
@@ -85,6 +85,7 @@
 
 	/* state variables, change over time */
 	var boolean g_rx_enabled := false;
+	var boolean g_tx_connected := false; /* Set to true after connect() */
 	var LIN2_BO_LAST g_tx_next_seq := 0;
 	var uint32_t g_tx_next_ts := 0;
 
@@ -347,6 +348,8 @@
 				log("Local Port is not an even port number!");
 				continue;
 			}
+
+			g_tx_connected := false; /* will set it back to true upon next connect() call */
 			res := RTP_CodecPort_CtrlFunct.f_IPL4_listen(RTP, g_local_host,
 								g_local_port, {udp:={}});
 			if (not ispresent(res.connId)) {
@@ -387,6 +390,7 @@
 				setverdict(fail, "Could not connect to RTCP socket, check your configuration");
 				mtc.stop;
 			}
+			g_tx_connected := true;
 			CTRL.reply(RTPEM_connect:{g_remote_host, g_remote_port});
 		}
 		[] CTRL.getcall(RTPEM_mode:{RTPEM_MODE_NONE}) {
@@ -466,7 +470,7 @@
 		}
 
 		/* transmit if timer has expired */
-		[] T_transmit.timeout {
+		[g_tx_connected] T_transmit.timeout {
 			/* send one RTP frame, re-start timer */
 			f_tx_rtp(g_cfg.tx_fixed_payload);
 			T_transmit.start;