Western Electric hand telephone sets

The Western Electric hand telephone sets are a series of telephones that were produced from 1927 by the Western Electric Company for the American Telephone and Telegraph Company (AT&T) and the Bell System. The series features the mouthpiece (transmitter) and the earpiece (receiver) combined into a hand-held unit, originally named a hand telephone, or handset. The handset would be held against the ear and in front of the mouth simultaneously, in contrast to earlier telephones in the Bell System where only the receiver was held against the ear, while the user spoke into a fixed transmitter mounted on a telephone stand or wall telephone. Hand telephone sets consist of three principal parts: the handset, a handset mounting, and an apparatus box, called variously desk set box, bell box, subscriber set, or just subset. This box is typically mounted on a wall or desk-side, and contains an electromagnetic bell ringer and a speech transformer, called induction coil, to connect the telephone to the telephone line wiring. The handset mounting is either a desk-top stand to cradle and secure the handset when not in use, or a small box mounted against a vertical surface or wall that featured a switch-hook for hanging the handset. Other American and foreign telephone manufacturers had already produced this type of telephone, often referred to as French phone. In the Bell System, hand telephones formally replaced the hitherto used deskstand, colloquially called candlestick, by the end of the 1920s, although reconditioned candlestick telephones remained in service for at least another two decades. The shape and styling of these telephones by Western Electric evolved from the candlestick. Three main styles resulted for use on the desk-top, designated the type A, type B, and type D handset mounting. A and B had a circular base, while type D is identified by its elliptical footprint. The most notable examples of telephones constructed from the handset mountings, are the model 102 and the model 202 telephones, variants which differed in their electric circuitry, with improvements of speech performance. In addition, the type C, and later type G, handset mountings were small wall-mounted units for hanging up the handset. The 1927 handset and its telephone stand marked a milestone in AT&T's telephone development and of the Bell System, as it represented a new design methodology, away from inspired invention and empirical testing and toward theoretical planning and quantitative testing and quality assurance. It became the origin of all later telephone instruments in the Bell System.

History

Hand telephones The concept of a hand-held one-piece device that a telephone user would hold against ear and in front of the mouth arose in London shortly after the official invention of the telephone. Although early patents by C. E. McEvoy and G. E. Pritchett did not yield commercial devices in 1877, R. G. Brown of New York succeeded the following year in devising a combined transmitter and receiver handset, that he used in a local telephone exchange system in the district of the New York Gold and Stock Exchange. Having little success in promoting the device elsewhere in the U.S., Brown left for France to become Electrical Engineer of La Société Générale des Telephones in Paris. There, his designs found resonance and adaptations became widely used in Europe, where they became known as French phones. In the following decade, Western Electric experimented with three handset types, which were produced in limited quantities. Derivatives were used in the early 1900s for use as linemen telephone sets, but none were found adequate for use in the Bell System. While already popular in other countries, Western Electric produced handsets for export into the European market, but the Bell System had more stringent requirements than any other administration, due to the long distances of communication involved.

Technical obstacles Two major technical problems prevented the handset from reaching production stage for use by subscribers in the Bell System. Firstly, the transmitters of the day did not work well unless oriented steadily in a vertical plane. A handset would be used in many positions and orientations. If operated at other angles, carbon granules in the transmitter would shift and move in an unacceptable manner, resulting in poor voice quality. The second hurdle to the acceptance of a common handset model was that audio from the receiver was picked up acoustically by the transmitter and amplified. This resulted in howling tones, due to the hollow handles providing an acoustic channel between receiver and transmitter. The problems were aggravated by the signal boosting circuitry used in the subscriber set which resulted in a strong signal (sidetone) at the receiver of the speech of the user. Sidetone is the reproduction of sound through a local path from the transmitter to the receiver in the telephone. It is desirable only to some fraction of volume so that the user has the assurance that the telephone is working correctly. Strong sidetone may cause users to lower the voice to unacceptable levels, so that the recipient receives insufficient signal level.

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