Rotary dial

1836

Although no longer in common use, the rotary dial's legacy remains in the verb "to dial (a telephone number)". ==History== From as early as 1836 onward, various suggestions and inventions of dials for sending telegraph signals were reported.

1878

After the first commercial telephone exchange was installed in 1878, the need for an automated, user-controlled method of directing a telephone call became apparent.

1890

Further development continued during the 1890s and the early 1900s in conjunction with improvements in switching technology. Almon Brown Strowger was the first to file a patent for a rotary dial on December 21, 1891, which was awarded on November 29, 1892, as .

1891

Addressing the technical shortcomings, Almon Brown Strowger invented a telephone dial in 1891.

Before 1891, numerous competing inventions, and 26 patents for dials, push-buttons, and similar mechanisms, specified methods of signalling a destination telephone station that a subscriber wanted to call.

Most inventions involved costly, intricate mechanisms and required the user to perform complex manipulations. The first commercial installation of a telephone dial accompanied the first commercial installation of a 99-line automatic telephone exchange in La Porte, Indiana, in 1892, which was based on the 1891 Strowger designs.

Further development continued during the 1890s and the early 1900s in conjunction with improvements in switching technology. Almon Brown Strowger was the first to file a patent for a rotary dial on December 21, 1891, which was awarded on November 29, 1892, as .

1892

Slow-release relays in the central office keep the phone from being disconnected by dial pulses. The first patent for a rotary dial was granted to Almon Brown Strowger (November 29, 1892) as , but the commonly known form with holes in the finger wheel was not introduced until about 1904.

Most inventions involved costly, intricate mechanisms and required the user to perform complex manipulations. The first commercial installation of a telephone dial accompanied the first commercial installation of a 99-line automatic telephone exchange in La Porte, Indiana, in 1892, which was based on the 1891 Strowger designs.

Further development continued during the 1890s and the early 1900s in conjunction with improvements in switching technology. Almon Brown Strowger was the first to file a patent for a rotary dial on December 21, 1891, which was awarded on November 29, 1892, as .

1896

In 1896, this system was supplanted by an automatic contact-making machine, or calling device.

1900

Further development continued during the 1890s and the early 1900s in conjunction with improvements in switching technology. Almon Brown Strowger was the first to file a patent for a rotary dial on December 21, 1891, which was awarded on November 29, 1892, as .

Large cities like New York would ultimately require a seven-digit number, but some tests in the early 1900s indicated that the short-term memory span of many people could not handle seven digits and many dialling errors due to memory lapse might occur (the documentation for these tests is lost).

1904

Slow-release relays in the central office keep the phone from being disconnected by dial pulses. The first patent for a rotary dial was granted to Almon Brown Strowger (November 29, 1892) as , but the commonly known form with holes in the finger wheel was not introduced until about 1904.

1915

Hence the first Panel automatic exchanges cutover in 1915 in Newark, New Jersey used "semiautomatic" operation with the local operator keying the number for the caller.

1917

For example: "RE7-xxxx" represented "REgent 7-xxxx", 'Regent' being a local exchange name used in Canada, derived from an earlier precursor telephone number, '7xxxx' –with callers actually dialing '73-7xxxx' (737-xxxx). The use of letters on dials was proposed in 1917 by W.

1919

While used in telephone systems of the independent telephone companies, rotary dial service in the Bell System in the United States was not common until the introduction of the Western Electric model 50AL in 1919. From the 1970s onward, the rotary dial was gradually supplanted by DTMF (dual-tone multi-frequency) push-button dialing, first introduced to the public at the 1962 World's Fair under the trade name "Touch-Tone".

1947

In 1947, area codes were introduced in the United States, so as to facilitate direct distance dialing first by operators, then by subscribers.

1950

An even higher number, 907 (higher because the 0 counts as 10), was Alaska. In the 1950s, plastic materials were introduced in dial construction, replacing metal which was heavier and subject to higher wear. Despite their lack of modern features, rotary phones occasionally find special uses.

Alphabetic designation of exchanges with Cyrillic letters (А, Б, В, Г, Д, Е, Ж, И, К, Л for each of the digits from 1 through 0 respectively) was also used for a short period in the Soviet Union in the 1950s and 1960s, but by the next decade this practice was largely discontinued. ==Function== To dial a number, the user puts a finger in the corresponding finger hole and rotates the dial clockwise until it reaches the finger stop.

1960

When Australia around 1960 changed to all-numeric telephone dials, a mnemonic to help people associate letters with numbers was the sentence, "All Big Fish Jump Like Mad Under Water eXcept Yabbies." However, such letter codes were not used in all countries. Dials outside Canada, the United States, and large cities in Britain (before all-figure dialling) usually did not bear alphabetic characters or an indication of the word "operator" in addition to numbers.

Alphabetic designation of exchanges with Cyrillic letters (А, Б, В, Г, Д, Е, Ж, И, К, Л for each of the digits from 1 through 0 respectively) was also used for a short period in the Soviet Union in the 1950s and 1960s, but by the next decade this practice was largely discontinued. ==Function== To dial a number, the user puts a finger in the corresponding finger hole and rotates the dial clockwise until it reaches the finger stop.

The LED and Zener diode were contained in the same package for ease of assembly in manufacturing. ===Push-button pulse phones=== In the UK, some early phones (in the mid to late 1960s) were built which continued to provide the same rotary-dial signalling on their PABX by using a separate converter to give 10-PPS, but were operated with buttons.

1962

While used in telephone systems of the independent telephone companies, rotary dial service in the Bell System in the United States was not common until the introduction of the Western Electric model 50AL in 1919. From the 1970s onward, the rotary dial was gradually supplanted by DTMF (dual-tone multi-frequency) push-button dialing, first introduced to the public at the 1962 World's Fair under the trade name "Touch-Tone".

1970

While used in telephone systems of the independent telephone companies, rotary dial service in the Bell System in the United States was not common until the introduction of the Western Electric model 50AL in 1919. From the 1970s onward, the rotary dial was gradually supplanted by DTMF (dual-tone multi-frequency) push-button dialing, first introduced to the public at the 1962 World's Fair under the trade name "Touch-Tone".

1980

For instance, the anti-drug Fairlawn Coalition of the Anacostia section of Washington, D.C., persuaded the phone company to reinstall rotary-dial pay phones in the 1980s to discourage loitering by drug purchasers, since they lacked a telephone keypad to leave messages on dealers' pagers.

1995

In the original system in use until 1995, the first digit of the area code could not be a one or a zero, but the second number had to be a one or zero.




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