Echo cancellation technology monitors the incoming and outgoing streams of a phone conversation. If it determines that the outgoing stream is the same as the incoming (an echo), the noise cancellation engine subtracts that part of the outgoing stream.
Echoes are usually caused by a phone with a strong speaker and a sensitive microphone that picks up a voice from the speaker and broadcasts it back through the microphone. This can happen, for example, when conversing on speaker phone. Echo cancellation eliminates these annoying echoes.
Echo cancellation is often used in call centers with interactive voice response (IVR) systems that use voice recognition. If a caller is on a speaker phone when they are interacting with the IVR, it could cause the IVR to hear and then try to process an echo of its own instructions. Echo cancellation engines prevent this from happening, saving some callers from having a bad customer experience.
