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.Bell Telephone Laboratories, Staff, M.D. Fagan (Ed.), A History of Engineering and Science in the Bell System–The Early Years (1875–1925), 1975, p.153
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,Frederick H.A., Bell Laboratories Record 12(11) 322 (July 1934), Early Handsets, p.323 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.Bell Telephone Laboratories, Staff, M.D. Fagan (Ed.), A History of Engineering and Science in the Bell System–The Early Years (1875–1925), 1975, p.140 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,BTL, Early Years, p. 144 but the Bell System had more stringent requirements than any other administration, due to the long distances of communication involved.BTL, Early Years, p. 142
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.AT&T, Bell System Practices, Section C30.001 Issue 1 (March 16, 1932) Common Battery Anti-Sidetone Stations 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.
Circuit theory and handset solutions During the 1910s, the reasons for these problems became well understood, but remedies remained elusive. After the end of World War I, new efforts concentrated on the resolution of these deficiencies, as new research yielded insight into electric circuit theory for anti-sidetone compensation, and new hope of progress. In the 1920s, developments of non-positional transmitters, which worked in any orientation, permitted Western Electric to develop a handset model essentially free of these problems. The construction of the handset was changed from using hollow metal handles to solid Bakelite, a molded plastic material that was gaining acceptance in the telephone industry. With the solid construction the engineers were able to suppress acoustic feedback from receiver to transmitter to acceptable levels, by elevating the mechanical resonance frequencies of the handset sufficiently to avoid interference with the speech range. The resulting device was ready for distribution around the start of 1927.
Alongside the development of the handset, engineers at Bell Telephone Laboratories also worked on improvements of telephone circuitry that assisted in the quality of speech conversion and transmission. While already used in telephone operator circuitry, this anti-sidetone circuit was not ready for the first hand telephones, but had to wait for the early 1930s.
Handset mountings The completed handset was paired with a stand that had been in used for several years in the development stages of the handset. It was essentially a candlestick base with a shortened shaft of approximately one and one half inch in height, topped with a new cradle for the handset. It was later referred to as the type A handset mounting.
The release of the new hand telephone set uncovered mechanical flaws, so that a new base was designed to replace the shortened candlestick. The result was the type B handset mounting introduced later in 1927. It still retained a circular footprint of the base, but improved on the esthetic appearance. The B-type desk set was followed by a wall-mounted hand telephone set, designated as the type C1, also referred to as a hangup telephone, with the handset hanging on one side of the unit in a switchhook fork that cradled only the receiver cup.
In use, the B-type telephone base proved unstable during dialing, and was replaced with the type D handset mounting by 1930. A wider, elliptical footprint improved its stability. The D handset mounting was initially deployed with the same electric circuit (booster circuit) as the prior models. This new style of telephone also prompted a modernization in style of the subscriber sets, yielding updated, smaller, and less costly units.
Anti-sidetone circuit While the construction of the handset with a solid Bakelite handle had eliminated the howling by mechanical (acoustic) feedback from the receiver to the transmitter, it did not reduce the electrical feedback from the transmitter to the receiver due to the coupling of these elements through the induction coil, which was particularly annoying in a noisy room, because the background noise could overwhelm the speech signal received from the distant party, and when speaking, users would hear themselves very loudly too. This was improved with the anti-sidetone speech circuitry which was finally introduced the following year (1931) in new sections for equipment in the Bell System Practices. However, with the onset of the worst years of the Great Depression, distribution of telephone sets with this new circuit was largely delayed. New and existing telephone service installations in the U.S. were in decline and staffing at Western Electric was reduced by eighty percent.
The anti-side tone circuit featured a three-winding induction coil, rather than a simple two-winding transformer. The third winding compensates a part of the sidetone by superimposing a phase-inverted portion of the transmitter signal.J. W. Foley, Bell Laboratories Record 17(11) 347 (July 1939) The Anti-Sidetone Station Circuit This reduced the loudness of the user's own speech in the receiver, but left enough to avoid complete silence in the ear of the user, which might be interpreted as a device failure.
Telephone assembly codes With the completion of the anti-sidetone circuit, in 1930 Western Electric began assigning assembly codes to telephones based on the type of electrical configuration.AT&T, Bell System Practices, Section C32.111 Issue 2 (December 1, 1937) Hand Telephone Sets, Desk Types–Description Until then, the hand telephone sets were primarily referred to by the handset mountings used to construct them. With the new circuit variant, this became insufficient, resulting in the distinction between 100-series and 200-series hand telephone sets. Thus, the type 102 was the new designation for a handset mounting when used on common battery lines with a side-tone circuit,AT&T, Bell System Practices Section C32.101 Issue 1 (1 August 1930), Hand Telephone Sets—B Types—Description and Use and the 202 was the anti-sidetone version.AT&T, Bell System Practices, Section C32.103 Issue 1 (1 June 1931) Anti-Sidetone Hand Telephone Sets–201, 202, 203, 205, 206, and 207 Types–Description and Use Initially, this referred to B-type handset mountings, but by the time the 200-series anti-sidetone hand telephone sets were documented in the Practices, the standard base was the D handset mounting. At that time, the 100-series assembly codes were also redefined by use of the D handset mounting,AT&T, Bell System Practices, Section C32.102 Issue 2 (1 June 1931) Sidetone Hand Telephone Sets–101, 102, 103, 104, and 105 Types–Description and Use so that the assembly code 102 was no longer used for A- or B-type handset mountings.AT&T, Bell System Practices, Section C44.101 Issue 2 (1 November 1931, Sidetone Hand Telephone Sets–101, 102, 103, 104, and 105 Types–Connections, p.1 However, they were covered by the same specifications and maintenance procedures.AT&T, Bell System Practices, Section C32.160 Issue 1 (1 November 1931) Sidetone Hand Telephone Sets–101, 102, 103, 104, and 105 Types–Cording
Type A handset mounting