diff --git a/library/MGCP_CodecPort.ttcn b/library/MGCP_CodecPort.ttcn
index 416ac36c5..c20698683 100644
--- a/library/MGCP_CodecPort.ttcn
+++ b/library/MGCP_CodecPort.ttcn
@@ -53,7 +53,7 @@ module MGCP_CodecPort {
 		   pout.msg := dec_MgcpMessage(oct2char(pin.msg)); - see
 		   https://www.eclipse.org/forums/index.php/t/1088893/
 		 */
-		pout.msg := { response := dec_MgcpResponse(oct2char(pin.msg)) };
+		pout.msg := dec_MgcpMessage(oct2char(pin.msg));
 	} with { extension "prototype(fast)" };
 
 	private function MGCP_to_IPL4_Send(in MGCP_Send pin, out ASP_Send pout) {