Full Duplex vs Half Duplex: What's the Difference?

Most organizations rely on conferencing systems to communicate daily. But most of us don’t fully understand how it receives and transmits audio to/from other locations.

There are three main types of communication channels in the consumer telecom world: half duplex, full duplex, and simplex. In this practical guide, we've outlined the difference between half duplex and full duplex communication modes, so you can be sure you’re using the right tools for your collaboration.
 

What’s the Difference Between Half Duplex and Full Duplex?

First, a half duplex system only allows one party to speak at any given time. Just like a walkie-talkie, when one party is talking, the other party receives audio but cannot interrupt or add to the signal. The first party "has the ball" until they've finished speaking and someone else takes over. If there are more than 2 parties on a conference call, everyone will hear the same person speaking, and then any of the other parties can take over when the speaker "passes the ball" (i.e. stops talking). As long as someone is speaking, though, the other microphones will be disabled.  

On the other hand, a full duplex system allows for simultaneous communication, because there are two dedicated signals for sending and receiving audio. This is the main distinction when comparing full duplex vs half duplex. It means one party can cut another party off mid-sentence and ask a question (or finish a thought). There's more flexibility in a full duplex design, because people can speak naturally and not worry about constraints. To facilitate this design, full duplex systems have built-in DSPs (digital signal processing) that eliminate echoes and make it easier to hear each other.
 

How Half Duplex and Full Duplex Communication Work

Since a half duplex system only allows for communication in one direction, there is no echo or feedback, because one microphone is active at a time. Conversely, a full duplex system must incorporate echo cancellation features to isolate any background noise buildup and feedback from other microphones. For instance, the FLX UC 500 conference phone relies on a full duplex design that can capture and play audio in both directions simultaneously. To make this possible, the device contains four embedded microphones with echo cancellation that optimizes in real time, depending on the environment. It's just one way to maximize sound quality in your conferencing space, and it works particularly well in small conference rooms.  
 

When to Use Full Duplex or Half Duplex Technology

Before investing in a full duplex or half duplex system, take a moment to consider your conferencing needs. Will you be hosting conferences with a variety of participants, or will you mostly be relaying information in a one-way fashion? If you plan on having in-depth conversations over video chat, a full duplex system is the best way to go. However, if the conferencing system will primarily be used to deliver updates to teams across an organization, you might be able to get by with a half duplex design.

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