In a full-duplex system, both parties can communicate with each other simultaneously.MonitorIt is an example of Simplex mode as the Monitor can only introduce output.TelephoneIt is example of full duplex as the parties at both ends of a call can speak and be heard by the other party simultaneously.Walkie-TalkieIt is an example of a half-duplex device is a walkie-talkie.KeyboardIt is an example of Simplex mode as the keyboard can only introduce input.