File:Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems (1921) (14569553288).jpg

Identifier: automatictelepho00smit (find matches)
Title: Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems
Year: 1921 (1920s)
Authors: Smith, Arthur Bessey, b. 1875 Campbell, Wilson Lee
Subjects: Telephone
Publisher: New York : McGraw-Hill
Contributing Library: University of California Libraries
Digitizing Sponsor: Internet Archive

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Text Appearing Before Image:
ed in Fig. 16, each first-selector section (ten switches)receives its traffic from a lineswitch board which belongs to a given hun-dred. In a certain sense that particular 100 lines, its lineswitches,first selectors, and connectors, may be said to belong together. But thisrelationship is binding only for the connectors. The lineswitches andthe first selectors may be grouped quite differently. The first selector banks are trunked to the second selectors accordingto levels and thousands, and according to like sections. The first level of all first selector banks must trunk to second selectorsin the first thousand, second level to second selectors in the second thou-sand, third level to the third thousand, etc. The trunks from A first selector banks are trunked to A second selec-tors in all the thousands. B first selector banks trunk to B second selec-tors in all the thousands. This grouping applies to all the sections. 14 AUTOMATIC TELEPHONY First Selectors 100 Trun L.Sw. I200 £ 2IOO q
Text Appearing After Image:
ConnectorFio. 16.—Ten-thousand-line exchange with lineswitches. T RUN KING 15 The combination of the above two schemes results in the arrangementof trunks shown. Consider the A first selectors. From the first levelof their banks run ten trunks to the A section of second selectors in thefirst thousand. From the second level of A first selector banks run tentrunks to the A second selectors in the second thousand. Likewise thethird level trunks to A second selectors in the third thousand. Thisis continued throughout all the levels. Consider the B first selectors. Their first bank level trunks to theB section of second selectors in the first thousand. The second leveltrunks to B second selectors in the second thousand. The third levelleads to B second selectors in the third thousand. This is continuedto all levels and thousands. In this way all first selector sections of a given letter trunk to allthousands to second selector sections bearing the same letter. Also eachsecond selector se

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