The telephone answering machine was introduced by the American manufacturer Code-A-Phone in 1958. These early machines were large, clunky, expensive devices that were mostly used by small businesses. They consisted of two separate tape players housed in a single cabinet. One played the outgoing message on a continuous-loop cartridge or cassette. The other was usually a reel-to-reel tape that recorded the incoming message. The phone company required these machines to be connected to the phone line through a coupler, owned and installed by the phone company. Installation costs ranged from ten to fifty dollars, and the customer also had to pay a monthly rental fee of three dollars to eight dollars for the coupler.

During the mid-1980s demand for telephone answering machines took off, attributed mainly to the large increase in single-person households and families with two wage earners who left homes and phones...