Pulse dialing

Dialing Tips circa 1950 American Telephone & Telegraph - Bell System

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• published: 23 Mar 2013
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more at http://phones.quickfound.net/ How to dial your telephone, with operator-voiced spokesmodel Susann Shaw. Public domain film from the Prelinger Archive, slightly cropped to remove uneven edges, with the aspect ratio corrected, and mild video noise reduction applied. The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original). http://creativecommons.org/licenses/by-sa/3.0/ http://en.wikipedia.org/wiki/Rotary_dial The rotary dial is a device mounted on or in a telephone or switchboard that is designed to send electrical pulses, known as pulse dialing, corresponding to the number dialed. The early form of the rotary dial used lugs on a finger plate instead of holes. Almon Brown Strowger filed the first patent for a rotary dial, U.S. patent #486,909, on December 21, 1891, that was later issued to him on November 29, 1892. The modern version of the rotary dial with holes was first introduced in 1904 but did not enter service in the Bell System until 1919.[citation needed] The rotary dial was gradually supplanted by Dual-tone multi-frequency pushbutton dialing, introduced at the 1962 World's Fair, which uses a keypad instead of a dial. Some telephone systems in the US no longer recognize rotary dialing by default, but will only support push-button phones... History From as early as 1836, there were various suggestions and inventions of dials for sending telegraph signals. 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. The rotary dial was invented by Almon Brown Strowger in 1891. There were numerous competing inventions, and 26 patents of dials, push-buttons, and similar mechanisms for signalling which telephone subscriber was wanted by a caller were issued prior to 1891. 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-patent designs. The original dial designs were rather cumbersome[vague] and development continued during the 1890s and early 1900s hand in hand with the switching technology. In the 1950s, plastic dials supplanted metal ones in most new telephone designs. Despite their lack of modern features, rotary phones occasionally find special uses. 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 the dials could not be used to call dealers' pagers. General form The dial, also called the finger wheel, is circular. Ten finger holes perforate it in a partial ring near the perimeter. The dial is mounted via a shaft extending from inside the telephone and sits approximately 1⁄4 in (6 mm) above a faceplate. The faceplate is printed with letters and numbers corresponding to—and visible through—each finger hole. In North America, traditional dials have letter codes displayed with the numbers under the finger holes in the following pattern: 1, 2 ABC, 3 DEF, 4 GHI, 5 JKL, 6 MNO, 7 PRS, 8 TUV, 9 WXY, and 0 (sometimes Z) Operator. Letters were associated with the dial numbers to represent telephone exchange names in communities having more than 9,999 telephone lines, and additionally given a meaningful mnemonic to facilitate memorization of individual telephone numbers by incorporating their exchange names. 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 1 is normally set at approximately 60 degrees clockwise from the uppermost point of the dial, or approximately at the 2 o'clock position, and then the numbers progress counterclockwise, with the 0 being at about 5 o'clock. A curved device called a finger stop sits above the dial at approximately the 4 o'clock position. Dials outside Canada, the United States, and large cities in Britain (before all-figure dialing) usually did not bear alphabetic characters or an indication of the word "operator" in addition to numbers.[citation needed] Alphabetic designation of exchanges was also used for a short period in the Soviet Union in the 1950s, 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 user then pulls out the finger, and a spring in the dial returns it to the resting position...