Full Duplex Vs. Half Duplex

by E.M. Rawes; Updated September 26, 2017
Half-duplex was more common in telephones until around 1993, Top Bits reports.

Communication between people has evolved. Many years ago, the only way we were able to communicate was by written letter or in person; then, we were able to communicate by radio; then, the telephone came about; finally, the Internet was introduced as form of communication. The radio, the telephone and various forms of communication over the Internet are either full-duplex or half-duplex methods. Full and half-duplex communication methods are similar in some ways, but different in others.

Full-Duplex

Full-duplex allows messages to be sent and received simultaneously.

Full-duplex means of communication, such as telephones, Internet voice calls and video calls, are capable of sending and receiving messages over the same channel at the same time, PC Magazine reports. In digital networks, full-duplex is attained with two pairs of wires. In analog networks, or digital networks that use a carrier, full-duplex is attained by dividing the line's bandwidth into a sending frequency and a receiving frequency, the Farlex Encyclopedia reports.

Half-Duplex

Half-duplex only allows messages to go in one direction at a time.

Half-duplex means of communication, such as walkie-talkies and two-way radios, are capable of sending and receiving messages; but they cannot send and receive simultaneously and only one party can speak at a time, according to Top Bits. Some answering machines that have a call-back mechanism are also half-duplex devices. Any device where the user can speak to another user, but the other user has to wait his turn to respond, is a half-duplex device, Business Dictionary reports.

Similarities

Both full- and half-duplex are means of duplex communication. Duplex means a device that enables you to talk to someone at another location on the same type of device. Full- and half-duplex have been used on computers, telephones and some speakerphones. Both full and half-duplex sound cards are available for computers, Top Bits reports. Full and half-duplex are also part of the evolution in communications technology.

Differences

While full-duplex allows simultaneous sending and receiving, half-duplex allow only sending, then receiving, or vice versa. While full-duplex allows both users to speak at the same time, half-duplex does not have the capability to allow both users to speak simultaneously. Top Bits says full-duplex can simulate a real life conversation between multiple people; half-duplex cannot achieve this. While full-duplex uses two pairs of wires or two frequencies, half-duplex uses a single circuit, the Farlex Encyclopedia reports.

About the Author

E.M. Rawes is a professional writer specializing in business, finance, mathematical and social sciences topics. She completed her studies at the University of Maryland, where she earned her Bachelor of Science. During her time working in workforce management and as a financial analyst, she reinforced her business and financial know-how.

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