Simplex is a type of communication in which data can only be transmitted in one direction. It is often used in contrast to duplex communication, in which data can flow bidirectionally (back and forth) between two devices.

Broadcasts, in which a single transmission is sent to many users, is a common type of simplex communication. For instance, radio broadcasts, television broadcasts, and Internet streaming are all examples of simplex transmissions. Since these mediums only need to transmit, rather than receive data, simplex communication is all that is necessary.

While simplex transmissions are sufficient for broadcasting, nearly all computer network protocols and computer interfaces are duplex, meaning they can both send and receive data. Some computer components, however, may include "simplex circuits," in which data can only flow in one direction.

Updated April 5, 2012

Definitions by

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

The goal of 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 Simplex 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.