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Full-duplex
Unlike half-duplex, in full-duplex communication, both devices can send and receive messages simultaneously. This means that when device A sends a message to device B, at the same time, device B can send a message to device A, thus eliminating the need to wait for the message to arrive. That way, the communication channel is available for both devices so that they can send and receive messages simultaneously . An analogy of full-duplex communication is the phone communication that is based on the talk directly method, as shown in Figure 2.9:
Figure 2.9. Phone communication, which represents the full-duplex communication channel