A revolutionary speakerphone
Ericsson’s first speakerphone was designed in the 1930s. In the 1940s, a model was introduced with a separately powered amplifier, a microphone and speaker, also placed separately, and a special telephone with extra buttons for switching between talking via the loudspeaker and microphone or speaking through the handset. This equipment was primarily intended for managers in an office environment. It was very cumbersome, but having such an advanced phone that left the hands free and eliminated the need to hold a receiver imparted status.
The problem was that disturbances could occur in the form of ambient noise, echoes, self-reverberation and squeals. When transistor technology was introduced in the 1950s, new prerequisites were created for developing a more functional speakerphone. The result was Ericovox, which was launched in 1959.
Ericovox was designed as a pyramid that contained all the speaker equipment. It was completely transistorized, and power was provided via the telephone line. Ericovox featured automatic voice control using amplifiers for outgoing and incoming speech, as well as regulator circuits for both amplifiers. The amplification was automatically increased in the direction of the speech, while it was decreased in the opposite direction. Switching was so fast that it was not noticed by the speaking parties. The amplification system in Ericvox was patented and was the first to use completely electronic voice control.
The Ericovox lacked a ring device and a handset and was therefore used with a conventional telephone, typically the Ericofon. Later version of the Ericovox were improved, in part by reducing the impact of noise, and in part by automatically adjusting the strength of the voice signal to the subscriber line characteristics.
Author: KV Tahvanainen
Ericovox in sound-proof test room.