Trimline telephone
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The Trimline telephone is a series of
telephone A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into e ...
s that was produced by
Western Electric The Western Electric Company was an American electrical engineering and manufacturing company officially founded in 1869. A wholly owned subsidiary of American Telephone & Telegraph for most of its lifespan, it served as the primary equipment ma ...
, the manufacturing unit of the
Bell System The Bell System was a system of telecommunication companies, led by the Bell Telephone Company and later by the American Telephone and Telegraph Company (AT&T), that dominated the telephone services industry in North America for over one hundr ...
. These telephones were first introduced in 1965 and are formally referred to as the ''No. 220 Hand Telephone Sets''. The Trimline was designed by Henry Dreyfuss Associates under the project direction of Donald Genaro; the firm had produced the previous post-war desktop telephone types for the
American Telephone & Telegraph Company AT&T Corporation, originally the American Telephone and Telegraph Company, is the subsidiary of AT&T Inc. that provides voice, video, data, and Internet telecommunications and professional services to businesses, consumers, and government agen ...
.


History

Hand telephone sets in the Bell System were first designed starting with the creation of the handset is 1927. This series of telephone evolved through several designs in the 1920s and 1930s, to refurbishments in the 1950s. They consisted of a table-top handset stand and a wall- or desk-mounted subscriber set that contained the components to connect the telephone to the telephone line, as well as an electromechanical bell ringer. After the introduction of the Princess telephone line, in 1959, the design motivation for the Trimline series was to create an alternative design that was stylish and easier to use than a traditional telephone. This was accomplished by moving the dial from the telephone's base to the underside of the handset, between the
earpiece In-ear monitors (IEMs) are devices used by musicians, audio engineers and audiophiles to listen to music or to hear a personal mix of vocals and stage instrumentation for live performance or recording studio mixing. They are also used by tele ...
and mouthpiece. The same concept was later used for
cellular telephone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link while ...
and
cordless telephone A cordless telephone or portable telephone has a portable telephone handset that connects by radio to a base station connected to the public telephone network. The operational range is limited, usually to the same building or within some short ...
models. To miniaturize the rotary dial sufficiently to fit in the Trimline handset, the designers invented an unusual moving fingerstop. Like in the Princess line, the dial was lit when the handset was removed from the base. The Trimline was also one of the first phones to use the predecessor of the now-ubiquitous
RJ11 A registered jack (RJ) is a standardized telecommunication network interface for connecting voice and data equipment to a service provided by a local exchange carrier or long distance carrier. Registration interfaces were first defined in th ...
modular phone plug and jack. Field trials for the first iteration of the Trimline, nicknamed the "Shmoo", started in 1959 in New Brunswick, NJ.W.E. Whidden, ''An Experimental "Dial-In-Handset"Telephone'', Bell Laboratories Record 38 (1) 23 (January 1960) Based on the trials, Western Electric modified the design several times, ultimately resulting in the Trimline, which was eventually introduced in 1965. The Trimline included a lighted dial and was encased in a sleek, curved molded-plastic housing that took up less space than earlier Western Electric telephones. However, the glass-smooth and shallowly-curved plastic handset proved difficult to retain between cheek and shoulder for hands-free communication without slipping. This problem was never corrected over the life of the model line. Third-party manufacturers offered cushioned clamp-on adaptors to make it easier to cradle the handset, but these add-ons were unsightly. The first Trimline models used incandescent dial lights powered by a power
transformer A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer' ...
plugged into a standard electrical outlet. The bulky transformer and the need for a conveniently-placed outlet was criticized by many consumers, but was necessary because of the power demands of the incandescent light bulb. Years later, Western Electric redesigned the Trimline to use a low-power green
light-emitting diode A light-emitting diode (LED) is a semiconductor Electronics, device that Light#Light sources, emits light when Electric current, current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy i ...
(LED) to backlight the dial, which was powered by current from the telephone line, eliminating the need for the transformer. Always eager to re-use its older stocks of turned-in rental phones, AT&T later repainted and sold early-model non-LED Trimlines as "non-lighted" models, without a transformer.


Variants

The Trimline handset was produced in both rotary dial and Touch-Tone versions. Rotary dial Trimline production began in late 1965 and a Touch Tone keypad was installed in mid-1966. The Trimline base was available in desk-top and wall-mount versions. The handsets and bases were interchangeable. The Trimline was the first US telephone to achieve design recognition in Europe, where it was referred to as the "Manhattan" model or the "Gondola". Today, similarly designed telephones are sold by many companies. AT&T retained the Trimline name for the later "Trimline III", a more compact successor featuring squared corners and straight lines. In the 21st century, Advanced American Telephones produces the Trimline models 205, 210 (based upon original design), and the 265, under license from AT&T.


Timeline

*1959 First customer trials of the Shmoo'', an early Trimline concept design. *1965 Original Trimline introduced in the winter of 1965. Only rotary dial versions produced that first year, and availability was limited. *1966 Touch Tone keypads become available in addition to dial models at mid-year. First touch-tone phones lack pound and star buttons and so only have ten buttons. *1968 Keypads on Touch Tone models were expanded to 12 keys, adding a pound and a star button to prepare for future functionality not yet available in 1968. *early 70s The clear plastic button backplate with colored paper backing matching the color of the phone is replaced with an aluminum backplate on the round button Touch-Tone phones. Also at this time, the round handset cords using proprietary connectors are replaced with modern flat modular cords and jacks. On all Trimline phones, the screw cover above the dial changes from reading "Bell System made by Western Electric" to just "Trimline" with a bell logo to the left of the text. *late 70s A green LED light fed by the phone line power replaces the incandescent lamp, additionally, the Touch-Tone version now sports slightly larger, square keys, as opposed to the earlier small round keys. Also the Touch-Tone version receives an aluminum faceplate behind the keys. *1983 AT&T begins selling phones, including the Trimline, to the public (as opposed to their previous leasing only policy) through its newly created
American Bell, Inc. AT&T Information Systems (ATTIS), originally known as American Bell, was the fully separate subsidiary of American Telephone & Telegraph Company (AT&T) which focused on computer technology ventures and telephone sales, and other unregulated busine ...
subsidiary. *1984 AT&T is divested of its regional operating companies and is prohibited from using the Bell name or logo, so the American Bell brand is dropped and replaced with simply AT&T. All telephone production continues as normal. **Late 1984 The Touch-tone Trimline phone is heavily modified with the following new features: ***Electronic chirp ringer in the handset, replacing the previous real bell ringer ***Keys are now made of a soft rubber material ***Line switch (switchhook) eliminated from base, moved to top of phone just below the receiver ***Handset screws' cover no longer says "Trimline"; made smaller in the middle to conform to new switchhook location ***Only one handset-to-jack cord is required for the telephone connection; cord can be tightly secured onto the bottom of the base, which now only exists with no purpose other than as a rest for the handset *1985 The rotary Trimline is discontinued, and further modifications are made to the touch-tone model: **Desk or wall convertible, eliminating separate desk and wall models **Touch-Tone/dial pulse switch, eliminating separate Touch-Tone and rotary models **Redial and Mute functions **One cord to connect telephone is eliminated, base-to-handset and base-to-jack cords reinstated *1986 With the closing of the Western Electric
Indianapolis Indianapolis (), colloquially known as Indy, is the state capital and most populous city of the U.S. state of Indiana and the seat of Marion County. According to the U.S. Census Bureau, the consolidated population of Indianapolis and Marion ...
Works, Trimline production is moved overseas to
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and
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...
. Minor modifications included: **Earpiece Volume Control **Chirp Ringer/ringer loudness switch moved to base of the phone **Bottom of the base is now made of plastic, with a lead weight inside the base **Only 1 screw is used to hold the handset together; location of screw and screw cover is moved to below the dialpad **2220 Trimline is dropped as a model number, replaced by the 210, 220, and 230. *1993 The Trimline phone is again updated with the following features: **The soft rubber keys are again replaced with hard plastic keys, similar to the late 70s and early 80s models, but the keys are even larger and rectangular rather than square **The faceplate behind the keys, aluminum since the late 70s LED conversion is now a dark gray plastic with a matte surface **Production is moved to
Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...
**Caller ID models, the 250 & 260, are introduced under the Trimline brand. The design shares nothing in common with the 210 model. *1996
Lucent Technologies Lucent Technologies, Inc. was an American multinational telecommunications equipment company headquartered in Murray Hill, New Jersey. It was established on September 30, 1996, through the divestiture of the former AT&T Technologies business u ...
is spun off from AT&T, and minor modifications are added: **Phones are marked "Lucent Technologies", though this turned out to be temporary, and the boxes and marketing materials were always co-branded with AT&T **"Trimline" again marked above the dialpad on the matte surface **Ringer loudness switch is moved back to dialpad; ringer remains inside the base *1997 Lucent enters a joint venture with
Philips Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters is ...
, creating Philips Consumer Communications. Shortly after, more changes are made: **Handset screws are eliminated completely. Handset is only held together by "snap" ends at both ends of the phone, above the receiver and below the microphone. **Telephones are again branded AT&T; Lucent Technologies branding ends. **Ringer moved into handset. *2000 Lucent dissolved the joint venture with Philips in 1998, and sells its consumer division to
Hong Kong Hong Kong ( (US) or (UK); , ), officially the Hong Kong Special Administrative Region of the People's Republic of China (abbr. Hong Kong SAR or HKSAR), is a List of cities in China, city and Special administrative regions of China, special ...
company VTech, where it becomes Advanced American Telephones. VTech moved all production to the
People's Republic of China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...
.


Powered modular jacks for illumination

In the Trimline version designed for connection to an
RJ11 A registered jack (RJ) is a standardized telecommunication network interface for connecting voice and data equipment to a service provided by a local exchange carrier or long distance carrier. Registration interfaces were first defined in th ...
telephone jack, pins 2 and 5 (black and yellow) may carry low-voltage AC or DC power. While the telephone line supplies enough power for most telephones, older telephone instruments with incandescent dial lights (such as the classic Western Electric Princess and Trimline models) needed different voltages and more current than the line could supply. Typically, the power came from a transformer plugged into a power outlet near the telephone jack, wired to supply power to just that telephone, or to all jacks in the house, depending on local
telephone company A telephone company, also known as a telco, telephone service provider, or telecommunications operator, is a kind of communications service provider (CSP), more precisely a telecommunications service provider (TSP), that provides telecommunicat ...
practices. It is now usually recommended that only the one local jack used by such older telephones be wired for power, to avoid any potential interference with other types of service that ''might'' be using pins 2 and 5 (black and yellow pair) in jacks in other parts of the house. The early Trimline and Princess incandescent lamps were rated at 6.3 volts and 0.25 amperes and the transformer output is approximately 6–8 volts AC. Later Trimline versions had LED light sources, powered directly from the phone line, and the last Western Electric-made Princess version had no dial light.


See also

* Contempra, a similar form factor handset designed by the Northern Electric Company, and deployed by
Bell Canada Bell Canada (commonly referred to as Bell) is a Canadian telecommunications company headquartered at 1 Carrefour Alexander-Graham-Bell in the borough of Verdun in Montreal, Quebec, Canada. It is an ILEC (incumbent local exchange carrier) in ...
.


References


External links


Western Electric Telephone Models


{{Western Electric telephones Western Electric telephones