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A rotary dial is a component of a telephone or a telephone switchboard that implements a signaling technology in telecommunications known as pulse dialing. It is used when initiating a telephone call to transmit the destination telephone number to a telephone exchange.
Direct distance dialing (DDD) is a telecommunication service feature in North America by which a caller may, without operator assistance, call any other user outside the local calling area. Direct dialing by subscribers typically requires extra digits to be dialed as prefixes to the directory telephone number of the destination. DDD also extends beyond the boundaries of the national public telephone network, in which case it is called international direct dialing or international direct distance dialing (IDDD).
In electronics, a crossbar switch is a collection of switches arranged in a matrix configuration. A crossbar switch has multiple input and output lines that form a crossed pattern of interconnecting lines between which a connection may be established by closing a switch located at each intersection, the elements of the matrix. Originally, a crossbar switch consisted literally of crossing metal bars that provided the input and output paths. Later implementations achieved the same switching topology in solid-state semiconductor chips or System on Chips (SoC). The cross-point switch is one of the principal switch architectures, together with a rotary switch, memory switch, and a crossover switch.
The Strowger switch is the first commercially successful electromechanical stepping switch telephone exchange system. It was developed by the Strowger Automatic Telephone Exchange Company founded in 1891 by Almon Brown Strowger. Because of its operational characteristics it is also known as a step-by-step (SXS) switch.
The Pacific Bell Telephone Company is a telephone company that provides telephone service in California. The company is owned by AT&T Inc. through AT&T Teleholdings, and, though separate, is now marketed as “AT&T”. The company has been known by a number of names during which its service area has changed. The formal name of the company from the 1910s through the 1984 Bell System divestiture was The Pacific Telephone and Telegraph Company. As of 2002, the name “Pacific Bell” is no longer used in marketing, Pacific Bell is still the holder of record for the infrastructure of cables and fiber through much of California.
The director telephone system was a development of the Strowger or step-by-step (SXS) switching system used in London and five other large cities in the UK from the 1920s to the 1970s.
A sender was a special type of circuit in 20th-century electromechanical telephone exchanges which registered the telephone numbers dialed by the subscriber, and then transmitted that information to another exchange. In some American exchange designs, for example, the No. 1 Crossbar switch there were both originating senders and terminating senders. The corresponding device in the British director telephone system was called a "director" and, in other contexts, "register".
A class-5 telephone switch is a telephone switch or telephone exchange in the public switched telephone network located at the local telephone company's central office, directly serving subscribers. Class-5 switch services include basic dial-tone, calling features, and additional digital and data services to subscribers connected to a local loop.
A marker is a type of special purpose control system that was used in electromechanical telephone central office switches. Switches employing markers belong to a class of switches known as "common control", as the purpose of a marker is to control the closure of contacts in the switching fabric that connect a circuit between the calling party and the called party. This is in contrast to "direct control" switches, where the switching elements were controlled directly by the customer's dial, such as the Step by Step switch. The term marker came from its use to mark a path of links through the switching fabric. A marker's comprehensive view of the switching fabric allowed it to find and assemble a path from one terminal to another, if the links were available, unlike the earlier graded progressive systems in which a path might not be found.
Area codes 408 and 669 are telephone area codes in the North American Numbering Plan (NANP) in the U.S. state of California. The numbering plan area comprises most of Santa Clara County and Northern Santa Cruz County, and includes Gilroy, Morgan Hill, Saratoga, Los Gatos, Monte Sereno, Milpitas, Sunnyvale, Santa Clara, Cupertino, Campbell, and San Jose.
The Number Five Crossbar Switching System is a telephone switch for telephone exchanges designed by Bell Labs and manufactured by Western Electric starting in 1947. It was used in the Bell System principally as a Class 5 telephone switch in the public switched telephone network (PSTN) until the early 1990s, when it was replaced with electronic switching systems. Variants were used as combined Class 4 and Class 5 systems in rural areas, and as a TWX switch.
A class-4, or tandem, telephone switch is a U.S. telephone company central office telephone exchange used to interconnect local exchange carrier offices for long distance communications in the public switched telephone network.
The Number One Crossbar Switching System, was the primary technology for urban telephone exchanges in the Bell System in the mid-20th century. Its switch fabric used the electromechanical crossbar switch to implement the topology of the panel switching system of the 1920s. The first 1XB system was installed in the PResident-2 central office at Troy Avenue in Brooklyn, New York which became operational in February 1938.
Foreign exchange service (FX) is an access service in a telecommunications network in which a telephone in a given exchange area is connected, via a private line, as opposed to a switched line, to a telephone exchange or central office in another exchange area, called the foreign exchange, rather than the local exchange area where the subscriber station equipment is located.
The original North American area codes were established by the American Telephone & Telegraph Company (AT&T) in the immediate post-WWII period. The effort of creating a comprehensive and universal, continent-wide telephone numbering plan in North America had the eventual goal of direct distance dialing by telephone subscribers with a uniform destination addressing and call routing system for all public service telephone networks. The initial Nationwide Numbering Plan of 1947 established eighty-six numbering plan areas (NPAs) that principally followed existing U.S. state or Canadian provincial boundaries, but fifteen states and provinces were subdivided further. Forty NPAs were mapped to entire states or provinces. Each NPA was identified by a three digit area code used as a prefix to each local telephone number. The initial system of numbering plan areas and area codes was expanded rapidly in the following decades and established the North American Numbering Plan (NANP).
The push-button telephone is a telephone that has buttons or keys for dialing a telephone number, in contrast to having a rotary dial as in earlier telephone instruments.
A PSTN network topology is the switching network topology of a telephone network connected to the public switched telephone network (PSTN).
A telephone exchange, telephone switch, or central office is a telecommunications system used in the public switched telephone network (PSTN) or in large enterprises. It interconnects telephone subscriber lines or virtual circuits of digital systems to establish telephone calls between subscribers.
The Panel Machine Switching System is an early type of automatic telephone exchange for urban service, introduced in the Bell System in the 1920s. It was developed by Western Electric Laboratories, the forerunner of Bell Labs, in the U.S., in parallel with the Rotary system at International Western Electric in Belgium before World War I. Both systems had many features in common.
References
- ↑ "For 15 years, the mark of an Atlanta newcomer: a 678 phone number". Saporta Report. 2013-01-28. Retrieved 2013-06-02.
- ↑ "Survey of Telephone Switching - Chapter 4". Telephone Tribute. Retrieved 2013-06-02.
- ↑ "Goliath's Fall | 2012-05-15". Microwave Journal. Retrieved 2013-06-02.Cite magazine requires
|magazine=(help) - ↑ "Telecommunications Virtual Museum". Telcomhistory.org. Archived from the original on 2013-06-19. Retrieved 2013-06-02.
