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The ringer equivalence number (REN) is a telecommunications measure that represents the electrical loading effect of a telephone ringer on a telephone line.In the United States, ringer equivalence was first defined by U.S. Code of Federal Regulations, Title 47, Part 68, based on the load that a standard Bell System model 500 telephone represented, and was later determined in accordance with ...
Alexander Graham Bell was awarded the first U.S. patent for the invention of the telephone in 1876. Elisha Gray, 1876, designed a telephone using a water microphone in Highland Park, Illinois. Tivadar Puskás proposed the telephone switchboard exchange in 1876. Thomas Edison invented the carbon microphone which produced a strong telephone ...
An extension bell or extension ringer[1] is a device that generates a sound to indicate an incoming telephone call, but is not included in a telephone set itself. Extension bells may be louder than ordinary telephone ringers. As such they may be used by persons with moderate hearing impairment to help them detect incoming telephone calls ...
3 April 1930: Opening of transoceanic telephone service to Argentina, Chile, and Uruguay and subsequently to all other South American countries. [23] 1931: The Ericsson DBH 1001 telephone was the first telephone without a separate ringer box. [32] 25 April 1935: First telephone call around the world by wire and radio. [23]
All-number calling. All-number calling (ANC) is a telephone numbering plan that was introduced into the North American Numbering Plan by the Bell System in the United States starting in 1958 [1] to replace the previous system of using a telephone exchange name as the first part of a telephone number. [2] The plan prescribed the format of a ...
Telephone directory. A telephone directory, commonly called a telephone book, telephone address book, phonebook, or the white and yellow pages, is a listing of telephone subscribers in a geographical area or subscribers to services provided by the organization that publishes the directory. Its purpose is to allow the telephone number of a ...
Telephone numbers listed in 1920 in New York City having three-letter exchange prefixes. In the United States, the most-populous cities, such as New York City, Philadelphia, Boston, and Chicago, initially implemented dial service with telephone numbers consisting of three letters and four digits (3L-4N) according to a system developed by W. G. Blauvelt of AT&T in 1917. [1]
A party line (multiparty line, shared service line, party wire) is a local loop telephone circuit that is shared by multiple telephone service subscribers. [1][2][3] Party line systems were widely used to provide telephone service, starting with the first commercial switchboards in 1878. [4] A majority of Bell System subscribers in the mid-20th ...