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The Number One Crossbar Switching System (1XB), was the primary technology for urban telephone exchanges served by 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 No. 1 Crossbar was installed in the PResident-2 central office at Troy Avenue in Brooklyn, New York which became operational in February 1938.
The Number One Electronic Switching System (1ESS) was the first large-scale stored program control (SPC) telephone exchange or electronic switching system in the Bell System. It was manufactured by Western Electric and first placed into service in Succasunna, New Jersey, in May 1965. The switching fabric was composed of a reed relay matrix controlled by wire spring relays which in turn were controlled by a central processing unit (CPU).
TXE, was a family of telephone exchanges developed by the British General Post Office (GPO), designed to replace the ageing Strowger switches.
Echo suppression and echo cancellation are methods used in telephony to improve voice quality by preventing echo from being created or removing it after it is already present. In addition to improving subjective audio quality, echo suppression increases the capacity achieved through silence suppression by preventing echo from traveling across a telecommunications network. Echo suppressors were developed in the 1950s in response to the first use of satellites for telecommunications.
The Panel Machine Switching System is a type of automatic telephone exchange for urban service that was used in the Bell System in the United States for seven decades. The first semi-mechanical types of this design were installed in 1915 in Newark, New Jersey, and the last were retired in the same city in 1983.
References
- ↑ ITU-T Recommendation Q.9 - Vocabulary of Switching and Signalling Terms
- ↑ R. F. Linfield (1978). "Access Area Switching and Signaling:Concepts, Issues, and Alternatives". 60. National Telecommunications and Information Administration: 61.
{{cite journal}}: Cite journal requires|journal=(help) - ↑ Leonard Lewin (1984). Telecommunications: An Interdisciplinary Text. Artech House. p. 332. ISBN 9780890061404.
- ↑ John G. van Bosse; Fabrizio U. Devetak (2006). Signaling in Telecommunication Networks. Wiley. p. 96. ISBN 9780470048139.