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The Strowger switch has three banks of contacts. Toward the upper end of each shaft are two ratchets. The upper one has ten grooves, and raises the shaft. The lower one has long vertical teeth (on the other side, hidden). The Strowger switch uses two telegraph-type keys on a telephone set for dialing. Each key requires a separate wire to the ...
Almon Brown Strowger (/ ˈ s t r oʊ dʒ ər /; February 11, 1839 – May 26, 1902) was an American inventor who gave his name to the Strowger switch, an electromechanical telephone exchange technology that his invention and patent inspired.
2 November 1889: A.G. Smith patents a telegraph switch which provides for trunks between groups of selectors allowing for the first time, fewer trunks than there are lines, and automatic selection of an idle trunk. 10 March 1891: Almon Strowger patents the Strowger switch the first Automatic telephone exchange.
Strowger may refer to: Strowger switch , automatic telephone exchange equipment Strowger Automatic Telephone Exchange Company , the company that manufactured Strowger switches
Slightly more complicated was the two axis stepping switch, (also called Strowger switch or two motion selector in Britain). Typically, a single compact group of wipers could connect to one of 100 (or 200) different fixed contacts, in ten levels. When the switch was idle, the wipers were disengaged from the fixed contacts.
Exchanges based on the Strowger switch were eventually challenged by other exchange types and later by crossbar technology. These exchange designs promised faster switching and would accept inter-switch pulses faster than the Strowger's typical 10 pps—typically about 20 pps.
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 U.S. patent 486,909. [ 4 ] [ 5 ] The early rotary dials used lugs on a finger plate instead of holes, and did not produce a linear sequence of pulses, but interrupted two independent circuits for control of ...
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 1980s. A large proportion (c. 70% to 80%) of telephone traffic in large metropolitan areas is outgoing traffic, and it is distributed over many exchanges.