A and B. Half-duplex network communications describes two devices networked together where only one device may communicate at any one time. The other device must wait until the first device is finished before initiating communications. Full-duplex describes a situation where two networked devices may transmit information to each other simultaneously, much in the same way two people can speak at the same time during a phone conversation. Solution A and B. Half-duplex network communications describes two devices networked together where only one device may communicate at any one time. The other device must wait until the first device is finished before initiating communications. Full-duplex describes a situation where two networked devices may transmit information to each other simultaneously, much in the same way two people can speak at the same time during a phone conversation..