Half-Duplex

Half-duplex is a type of communication in which data can flow back and forth between two devices, but not simultaneously. Each device in a half-duplex system can send and receive data, but only one device can transmit at a time.

An example of a half-duplex device is a CB (citizens band) radio. The CB protocol, which is used by truckers, police officers, and other mobile personnel, allows users to communicate back and forth on a specific radio frequency. However, since the CB protocol only supports half-duplex communication, only person can speak at a time. This is why people communicating over two-way radios often say "over" at the end of each statement. It is a simple way of telling the recipient he or she can respond if necessary.

Most communication protocols are designed to be full-duplex, rather than half duplex. Full-duplex communication allows computers and other devices to communicate back and forth at the same. While some computer networks can be set to half-duplex mode to limit bandwidth, full-duplex communication is much more common.

NOTE: Half-duplex is sometimes abbreviated "HDX."

Updated April 5, 2012

Definitions by TechTerms.com

The definition of Half-Duplex on this page is an original TechTerms.com definition. If you would like to reference this page or cite this definition, you can use the green citation links above.

The goal of TechTerms.com is to explain computer terminology in a way that is easy to understand. We strive for simplicity and accuracy with every definition we publish. If you have feedback about the Half-Duplex definition or would like to suggest a new technical term, please contact us.

Want to learn more tech terms? Subscribe to the daily or weekly newsletter and get featured terms and quizzes delivered to your inbox.

Sign up for the free TechTerms Newsletter

How often would you like to receive an email?

You can unsubscribe or change your frequency setting at any time using the links available in each email.

Questions? Please contact us.