Tài liệu Communication Concepts

Data Transmission Modes:
There are three ways in which data can flow in a circuit: one way only, one way at a time or both directions simultaneously.
Simplex Data can flow in only one direction. Examples are radio, TV, computer to printers, public address systems or any other unidirectional transmission.
Half-Duplex Data flows in only one direction at a time. It is sometimes called two-way alternate. Communication occurs in one direction and then the line is “turned around” and information flows in the other direction. CB radio is half-duplex.
Full Duplex Data flows in both directions at the same time. Most modem connections today transmit full duplex increasing efficiency with data flowing on the same pair of wires in both directions simultaneously.