Introduction to Data Communications
Previous	11. Timing (cont'd)	Next

11b. Data Flow

• Simplex
• Half Duplex
• Full Duplex

Simplex

During simplex communication, data flows in only one direction on the communication medium. It flows from the source to the destination. Examples of simplex data flow are Radio and Television broadcasts. They go in one direction from the transmitting site to your home receiver.

Half Duplex

During half duplex communication, data flows in both directions but only one direction at a time on the data communication line. The source and destination take turns using the medium. An example of half duplex communication is a conversation on walkie-talkies. Each person takes a turn talking. If both talk at once - nothing occurs!

Bi-directional but only 1 direction @ a time!

HALF-DUPLEX

Full Duplex

During full duplex communication, data flows in both directions simultaneously. Both source and destination can send data at the same time over the medium. An example of full duplex communication is communication using a modems. Modems are configured to allow data flow in both directions at the same time. The source is allowed to send data to the destination while the destination is sending data back.

Bi-directional both ends communicate simultaneously!

FULL-DUPLEX

Introduction to Data Communications
Previous	Table of Contents	Next