Modes of Data Communication refers to the direction of data flow from sender to receiver or vice-versa. There are basically three modes of data communication:- 1. Simplex: In this mode the communication is unidirectional . Only one of the two devices on a link can transmit and the other can only receive .i.e data travels in one direction. Example: radio, television, loudspeaker 2. Half-Duplex: In this mode, each device on the link has the ability to both transmit and receive, each at a time . When one device is sending, the other can only receive and vice versa. Example: walkie-talkie 3. Full-Duplex: In full-duplex mode, both the devices can transmit and receive simultaneously .i.e data can travel in both directions at the same time. Here the communication is bidirectional . Example: Telephone