Echo Suppressor

An echo suppressor (sometimes "acoustic echo suppressor", AES) is a telecommunications device used to reduce the echo heard on long telephone circuits, particularly circuits that traverse satellite links. Echo suppressors were developed in the 1950s in response to the first use of satellites for telecommunications, but they have since been largely supplanted by better performing echo cancellers.

Echo suppressors work by detecting a voice signal going in one direction on a circuit, and then inserting a great deal of loss in the other direction. Usually the echo suppressor at the far-end of the circuit adds this loss when it detects voice coming from the near-end of the circuit. This added loss prevents the speaker from hearing his own voice.