A common source of echo in VoIP phone systems is the telephone handsets. Of course, non-VoIP phone systems have this source of echo too, but it often is not so evident because without the buffering the echo delay is not as long.
Old Bell 500 series telephones have a wad of cotton wool in the handset to prevent sound from traveling from the receiver, through the hollow handset body, to the transmitter. But, many modern telephone handsets lack this important component. Here I show how I added cotton wool to the handset of a Linksys SPA-841 in order to reduce echo.
Continue reading Reducing Echo in Telephone Handsets