The
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 ...
model 500 telephone series was the standard domestic desk
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 ...
set issued by 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 ...
in North America from 1950 through the 1984
Bell System divestiture
The breakup of the Bell System was mandated on January 8, 1982, by an agreed consent decree providing that AT&T Corporation would, as had been initially proposed by AT&T, relinquish control of the Bell Operating Companies, which had provided loc ...
. Millions of model 500-series phones were produced and were present in most homes in North America. Many are still in use today because of their durability and ample availability. Its modular construction compared to previous types simplified manufacture and repair, and facilitated a large number of variants with added features.
Touch-tone
Dual-tone multi-frequency signaling (DTMF) is a telecommunication signaling system using the voice-frequency band over telephone lines between telephone equipment and other communications devices and switching centers. DTMF was first developed ...
service was introduced to residential customers in 1963 with the model 1500 telephone, which had a push-button pad for the ten digits. The model 2500 telephone, introduced in 1968, added the
* and
# keys, and is still produced by several manufacturers.
History
The Western Electric 500-type telephone replaced the
300-type, which had been produced since 1936. The model 500 line was designed by the firm of
industrial design
Industrial design is a process of design applied to physical Product (business), products that are to be manufactured by mass production. It is the creative act of determining and defining a product's form and features, which takes place in advan ...
er
Henry Dreyfuss
Henry Dreyfuss (March 2, 1904 – October 5, 1972) was an American industrial design pioneer. Dreyfuss is known for designing some of the most iconic devices found in American homes and offices throughout the twentieth century, including the We ...
, the product of several years of research and testing in collaboration with Bell Laboratories and Western Electric. Development started in 1946 with early sketches by Bell engineer and Dreyfuss associate Robert Hose, leading to pre-production units in 1948 and field trials with 4000 telephone sets in 1949. AT&T announced the new telephone publicly in 1949 and communicated the first availability of approximately 23,000 sets in the second quarter of 1950 to the Bell System operating companies on May 1, 1950. Third and fourth-quarter production was estimated at 49,000 and 93,000, respectively. Including 20,000 units of a special purpose set (501B), approximately 183,000 units were produced by the end of the first production year.
In the following years, the systematic replacement of 25 million 300-type telephones commenced because of the new model's much improved electrical and acoustic efficiency. This efficiency permitted the new model to be used on long rural
loops, which previously required special sets with local batteries to power the transmitter, not just on urban short loops because it contained a self-adjusting gain control. This also permitted the use of thinner loop wires and thus delivered cost savings in the build-out of the network.
The replacement of 300-series telephones with 500-series sets created large stockpiles of 300-type components that had not reached their intended service life. The accelerating demand for new telephone service in the 1950s created pressure on the manufacturing facilities, which the Bell System alleviated by reusing these older components to refurbish used 302 telephone sets with a new modern housing that had a look-alike appearance to the 500 models, but were electrically identical to the older 302 telephones. This program commenced in 1955, and the converted set was labeled as the
model 5302 telephone
The model 5302 telephone was introduced in 1955 by Western Electric as a look-alike product to the 500-type telephone to meet the increasing post-World War II demand for a modernized telephone, while reusing existing component supplies from the ...
. It was produced until the mid-1960s in the refurbishing shops of each
Bell Operating Company
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 hundre ...
, not on the assembly lines of Western Electric factories.
From the 1949 field trials until 1953, only black sets of the 500-type telephone were manufactured. Telephones in color were introduced in several stages from 1954 until 1957, as manufacturing capability was refined and material selection processes were completed.
In the 1960s, after the introduction of touch-tone service in November 1963 in various locations of the telephone network, the basic 500-type chassis was retrofitted with a
push-button
A push-button (also spelled pushbutton) or simply button is a simple switch mechanism to control some aspect of a machine or a process. Buttons are typically made out of hard material, usually plastic or metal. The surface is usually flat or sh ...
keypad, along with new housing and faceplate, creating the model 1500 for the 10-button version and in 1968 the model 2500, having 12 keys.
The 1970s brought the conversion to
modular connector
A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such as in computer networking, telecommunication equipment, and audio headsets.
Modular connectors were originally developed fo ...
technology, replacing the hard-wired cords with cords terminated on both ends with
4P4C connectors for the handset cord and
6P4C
A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such as in computer networking, telecommunication equipment, and audio headsets.
Modular connectors were originally developed fo ...
plugs for the line cord.
Ownership and AT&T divestiture
As with most telephones in the United States, the 500-series telephones were owned by the local
Bell Operating Company
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 hundre ...
and leased on a monthly basis to customers. Choices for telephone styles and colors were limited. AT&T, the principal owner of the operating companies and Western Electric, strictly enforced policies against buying and using telephone sets by other manufacturers on their network to ensure the technical integrity of their network and avoid competition. Most phones made by Western Electric, starting in about 1968, carried this disclaimer molded into their housing: "BELL SYSTEM PROPERTY--NOT FOR SALE." Telephones were also sometimes labeled with a sticker or ink stamp marking the operating company's name that owned the phone. After consumers started buying telephones from other manufacturers, in the wake of legal developments not favoring AT&T's ban against third-party equipment, AT&T changed its policy for the
Design Line telephone
A design is a plan or specification for the construction of an object or system or for the implementation of an activity or process or the result of that plan or specification in the form of a prototype, product, or process. The verb ''to design'' ...
series by selling customers the telephone housing but retaining ownership of the electrical components, so customers were still required to pay AT&T a monthly leasing fee.
In 1983, after the court ordered the
Bell System divestiture
The breakup of the Bell System was mandated on January 8, 1982, by an agreed consent decree providing that AT&T Corporation would, as had been initially proposed by AT&T, relinquish control of the Bell Operating Companies, which had provided loc ...
, AT&T started selling telephone sets outright to the public through its newly created
American Bell division. Many customers were offered the option to buy the leased telephones they had in service. AT&T closed its USA consumer telephone manufacturing plants in 1986 and moved production
offshore to Singapore, China, and Thailand, and in the 1990s to Mexico; this let them produce telephones at a lower cost.
Design features
The Western Electric model 500 improved upon several design features over the earlier telephones. While the 302 had the dial and hook switch mounted directly on the metal or plastic housing, all operational parts of the 500 telephone were mounted on the base plate, and the housing only contained two plungers to activate the hook switch when the handset was lifted from the cradle. Thus, the phone could be tested and serviced easily without the housing. This design improved manufacturing and servicing efficiency. The earlier 302 had been equipped with an enamel-coated dial plate that displayed the numerals and letters through the holes of the rotary finger-wheel. Years of use caused the lettering and numbering, and even the porcelain coating, to wear off. The design of the 500 improved this by molding the characters into the plastic through a double-injection molding process. This design was carried over to the 1500 and 2500-series telephones and was used in the touch-tone keys to eliminate wear. The numbers and letters on the 500 were moved to the circumference of the dial plate to make them visible from a wide range of viewing angles even while the dial was spinning back to its resting position. Dots were placed in the center of the finger holes as targets to help position the finger quicker for dialing of the next digit while the wheel was still spinning back. After extensive testing, this arrangement had the benefit of reducing dialing errors and increasing the speed of dialing each digit by fractions of a second. The 500 series replaced many metal parts, especially in the dial, with much more durable Nylon components.
The
Dreyfuss design later adapted itself well to touch-tone service, first announced in 1963. The earliest experimental touch-tone phones used the original Dreyfuss design almost unchanged; the
keypad
A keypad is a block or pad of buttons set with an arrangement of digits, symbols, or alphabetical letters. Pads mostly containing numbers and used with computers are numeric keypads. Keypads are found on devices which require mainly numeric in ...
, in varying layouts, was placed in a roundel in the dial opening, with the subscriber number label in a small window below. The 1500 and 2500 models adopted a more angular design style; the curves of the original design gave way to raised borders forming a lip around the finely-ribbed faceplate, in the middle of which the keypad and number window was centered.
Electrically and acoustically, the 500-series telephones had better efficiency and gain characteristics than their predecessors. The transmission efficiency was 5dB higher, and the receiver efficiency was 2.5dB better on long loops than on the 300-series telephones. A significant improvement was the use of equalization circuitry to achieve automatic gain adjustment. The sets could be deployed with equal performance on short or long local loops from the central office. The G-type handset was newly developed to help realize this efficiency. The older F series handset was already operating at the peak of its acoustic and electrical design efficiency. The G handset remains the standard handset on many phones, including public
payphone
A payphone (alternative spelling: pay phone) is typically a coin-operated public telephone, often located in a telephone booth or in high-traffic outdoor areas, with prepayment by inserting money (usually coins) or by billing a credit or debit ...
s.
For the initial years, from 1950 to 1953, the 500 was available only in black with a metal finger wheel. In 1954, color telephone sets were available in ivory, green, dark gray, red, brown, beige, yellow, and blue.
[AT&T, ''Colored Station Sets'', Bell System Practices Section C30.011, Issue 6, December 1953.][AT&T, ''Telephone Sets, 500-Type, Colors'', Bell System Practices Section C14.002 Issue 1 July 1955] Gray, blue, yellow, and red sets were initially assembled with black dials until the colored parts became available by 1955. So-called ''two-tone'' color varieties were available, which consisted of a black set having the housing substituted with a color plastic part.
They were offered as an attractive color combination for a reduced fee from the price of a full-color telephone. In 1957, gray, blue, beige, and brown sets were replaced with lighter pastel hues in light gray, aqua blue, light beige, white, and pink colors. Issuance of brown sets continued for multi-line business sets for several years. Turquoise sets were added in 1964, and several colors, including pink and light gray, were discontinued in the late 1960s.
By 1955, all color 500s were produced with clear finger wheels, while black sets retained the metal finger wheel until about 1964 when a new dial design was released.
Construction
The 500-type telephone consists of a rotary dial, a handset cradle, switch hook, and a handset (sometimes called the ''receiver'') wired to the base and has a molded plastic housing covering a steel chassis. The user interface consists of only the dial and switch hook buttons. No other components, switches, or controls are necessary, except a loudness control for the ringer, which is accessible on the bottom of the phone. The handset cradle is a molded part of the housing, formed of two U-shaped ''chairs'' that cradle the handset's handle between the receiver and the transmitter cups. Each side of the cradle has a round plastic plunger positioned above a pair of levers connected in a spring-loaded yoke that operated the hook switch; pressing the plungers down, end the call, and place the phone on hook. The plastic face of the dial under and surrounding the finger wheel is a part of the dial assembly and is exposed through the circular opening in the housing. On the bottom, the flat steel plate of the chassis is exposed. The handset cord exits from the left side of the housing at the base, and the line cord emerges from the rear at the base.
Internally, the phone contains circuitry composed of many passive electrical, electronic, and mechanical components. The set needs no separate power supply as it is received transmitter current from the telephone line; when it is on hook and not ringing, it uses no power, as the ringer is isolated with a capacitor from the direct current (DC) potential of the local loop.
The most complex part is the rotary dial mechanism, an assembly of gears, cams, springs, and electrical contacts which mechanically generate a timed train of
line loop-break pulses when the dial finger wheel is released after rotation. During the period of dial rotation, the receiver is shunted to avoid hearing the dial pulses.
![Westernelectricmodel500networkcloseupDSCN0258](https://upload.wikimedia.org/wikipedia/commons/0/04/Westernelectricmodel500networkcloseupDSCN0258.JPG)
The electromechanical ringer consists of two bell gongs of slightly different dimensions to produce different pitches and a striker between them that is driven by a
solenoid
upright=1.20, An illustration of a solenoid
upright=1.20, Magnetic field created by a seven-loop solenoid (cross-sectional view) described using field lines
A solenoid () is a type of electromagnet formed by a helix, helical coil of wire whose ...
; when the solenoid is energized by
alternating (AC) ringing current, typically about at , it strikes the two gongs alternately, producing a distinctive effect of two superimposed sounds. In telephones with a ringer loudness control, one gong is mounted off-center on the loudness control wheel; turning the wheel moves the gong toward (quieter) or away (louder) from the striker. The model 500 ringer was fairly loud and could be heard a few rooms away. The ringer could not be turned off on-the-fly but could be disabled in the wiring. When the phone was subjected to mechanical shock, the striker may hit the brass bells to sound a short ring. This effect was faithfully represented in various films and television shows.
The model 500 telephone was designed for long service life. Telephones in the Bell System were owned by and leased from the telephone company, which was responsible for keeping them in good repair. The phones were rugged and reliable and intended to last for decades with little maintenance. The 1940s-era technology of the 500 made extensive use of metal components and point-to-point wiring, and most components were modular and easy to remove and replace. The wiring system employed wires terminated with crimped spade lugs and slotted-screw terminals; most electrical connections in the phone could be disconnected or reconnected with a standard screwdriver.
Originally, the line cord and handset cord were secured by screw-down terminals at both ends, with a strain relief anchor. Both cords had matching colors, but most color sets initially were produced with neutral, dark gray cords, with exception of the ivory and brown sets. Starting in 1955, all sets, except dark blue were equipped with color-matched cords as dyes and manufacturing methods became stable. By 1973, line cords were changed to a neutral gray color and from a round to a flat cross-section. As a customer option, telephone sets could be ordered for portability with four-prong plugs, but most sets were hard-wired to wall connection boxes. In the 1970s, much smaller
modular connector
A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such as in computer networking, telecommunication equipment, and audio headsets.
Modular connectors were originally developed fo ...
s were introduced for both ends of the line cord as well as the handset cord to facilitate standard connection methods for third-party equipment within the FCC registration system.
Development
Several telephone models were derived from the basic model 500, using some of the same components. The model 554 was a wall-mounted version. Other special-purpose models included additional features. This included phones with dial lights (500U), party line sets (501), keysets (540 and 560 series), call directors, panel phones (750 series), industrial and outdoor phones (520 and 525), and automatic dialers (660).
Starting in 1963, the
Dreyfuss design adapted itself well to the newly announced Touch Tone® service. For the trial period, the dial was replaced with circular closure containing a
keypad
A keypad is a block or pad of buttons set with an arrangement of digits, symbols, or alphabetical letters. Pads mostly containing numbers and used with computers are numeric keypads. Keypads are found on devices which require mainly numeric in ...
and a telephone number label. The 1500 and 2500 models adopted a more rectangular design style; the curves of the original design gave way to raised borders forming a lip around the finely-ribbed faceplate, in the middle of which the keypad and number window was centered.
Standard touch-tone telephones generate twelve DTMF signals in a grid of three columns and four rows of buttons. In contrast, some special purpose telephones are equipped with a fourth column of keys for the A, B,C, and D DTMF signals for service priorities in the
AUTOVON system. Original sets used a transistor oscillator; newer phones use an integrated circuit. The model 1500 only had push buttons for the ten digits, while the model 2500 used 12 keys and included the '*' and '#' DTMF signals to allow for extra signaling needed in advanced service features, such as voice response systems and call management.
Other manufacturers
Beginning in the early 1950s, 500-style phones were also made under license by
ITT Kellogg (now
Cortelco
Kellogg company logo as used from the 1920s to the 1950s.
The Kellogg Switchboard and Supply Company was an American manufacturer of telecommunication equipment. Anticipating the expiration of the earliest, fundamental Bell System patents, Milo ...
), who continued manufacturing the original rotary design, marketed as the Cortelco ITT-500AS (desk phone) and Cortelco ITT-554AS (wall phone), until discontinuation on January 1, 2007. The design was also produced in Canada by
Northern Electric
Northern Electric was an electricity supply and distribution company serving north east England.
History
It had its origins as the North Eastern Electricity Board, formed as part of the nationalisation of the electricity industry by the Elect ...
, which eventually became Northern Telecom. Cortelco continues to produce a non-dial version of the model 500, known as the Model 89001047PAK; this phone is available only in bright red color.
Stromberg-Carlson (now part of
Siemens
Siemens AG ( ) is a German multinational conglomerate corporation and the largest industrial manufacturing company in Europe headquartered in Munich with branch offices abroad.
The principal divisions of the corporation are ''Industry'', '' ...
) also made the phones from the 1950s-1980s.
Replicas
Some contemporary replicas of the 500 model are available. While faithful from a cosmetic point of view, they are internally very different from the original, including a rotating tone dialer based on optical technology.
In popular culture
The Model 500 series, and its distinctive ring, are near-ubiquitous in late 20th-century U.S. and Canadian film and television. Model 500s are featured as a weapon in the movie ''
True Lies
''True Lies'' is a 1994 American spy action comedy film written and directed by James Cameron. It stars Arnold Schwarzenegger, Jamie Lee Curtis, Tom Arnold, Art Malik, Tia Carrere, Bill Paxton, Eliza Dushku, Grant Heslov and Charlton Heston. ...
''.
Touch-tone successors
Model 1500
The Western Electric model 1500 telephone adapted the 500 design for
touch-tone
Dual-tone multi-frequency signaling (DTMF) is a telecommunication signaling system using the voice-frequency band over telephone lines between telephone equipment and other communications devices and switching centers. DTMF was first developed ...
dialing with a push-button pad for the digits 0 through 9. It was produced from 1963 to 1968. In addition to the basic single-line model 1500D, the 1500-series included many related variations and special purpose models with additional features. This included sets with a headset jack, 2-line sets (1510F), key sets (1560), call directors, panel phones (1750), industrial phones (1520), and automatic dialers (1660).
Model 2500
By the late 1960s, interactive response systems in some industries required additional signaling beyond the ten digits. In 1968, the push-button dial pad was extended with two additional keys, the
# (''pound'') and
* (''asterisk''), which marked the introduction of the 2500-type telephone. The additional keys were located on either side of the ''0'' button to fill the matrix of 4-by-3 keys. These keys were initially unused by most customers but would later be used for
vertical service codes
A vertical service code (VSC) is a sequence of digits and the signals star (*) and number sign (#) dialed on a telephone keypad or rotary dial to enable or disable certain telephone service features. Some vertical service codes require dialing o ...
and
voice mail
A voicemail system (also known as voice message or voice bank) is a computer-based system that allows users and subscribers to exchange personal voice messages; to select and deliver voice information; and to process transactions relating to ind ...
menu navigation. In 1974, when modular connectors were introduced, the 2500 telephone was fitted with modular connectors on handset and line cords, resulting in type designations suffixed with ''M'', e.g., 2500DM. The 2500 is still commonly encountered and it is still produced by several companies.
In addition to the basic single-line model, the Western Electric 2500-series included many related variations and special purpose models with additional features. This included sets with a headset jack, 2-line sets, keysets (2560), call directors, panel phones (2750), industrial phones (2520), automatic dialers (2660).
See also
*
Model 5302 telephone
The model 5302 telephone was introduced in 1955 by Western Electric as a look-alike product to the 500-type telephone to meet the increasing post-World War II demand for a modernized telephone, while reusing existing component supplies from the ...
References
External links
*http://www.porticus.org/bell/telephones-500.html Western Electric Model 500
*http://www.arctos.com/dial/ Western Electric Telephone Models
*https://web.archive.org/web/20090530000805/http://www.cortelco.com/pdf/2008SolGuide.pdf
{{DEFAULTSORT:Model 500 Telephone
Telephony equipment
Western Electric telephones