Hi Simon I am implementing FECC in my Application. The following code snippet of h323.cxx.opens H323_H224 channel only in one direction i.e in Transmit direction only. #ifdef H323_H224 if(h245_available && startH224) { if(remoteCapabilities.FindCapability("H.224") != NULL) { H323Capability * capability = localCapabilities.FindCapability("H.224 "); if(capability != NULL) { if(logicalChannels->Open(*capability, OpalMediaFormat::DefaultH224SessionID)) { H323Channel * channel = capability->CreateChannel(*this, H323Channel::IsTransmitter, OpalMediaFormat::DefaultH224SessionID, NULL); if(channel != NULL) { channel->SetNumber(logicalChannels->GetNextChannelNumber()); fastStartChannels.Append(channel); } } } } startH224 = FALSE; } #endif Receiver channel is not being open. How to open H323_H224 Receiver channel ? Pls help me.. Regards Alam