Television by 'Phone

Radio Record, Volume II, Issue 28, 25 January 1929, Page 32

Television by 'Phone

HE well-known American Bell Telephone Laboratories, which were responsible for the first public demon stration of moving-picture transmission by wireless, have recently: designed a two-way television apparatus intended for use with the ordinary telephone service. It enables a sub-, , scriber at one end of the line to see, © as well as hear, the person at the other end of the line. The ordinary microphone is backed by a screen containing two apertures. The features of the distant person appear in one aperture, whilst the other receives the reflected light from the head and shoulders of the local speaker. A rotating disc with two series of spiral holes serves the dual purpose cof analysing the outgoing television signals and of reassembling the incoming television currents after they have been applied to a local Neon glowlamp. Four connecting line wires are necessary. One for carrying speech, one’ for carrying the outgoing television currents. one for the incoming television signals, and the fourth for carrying a synchronising current.