Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems (1921)
Smith, Arthur Bessey, b. 1875, Campbell, Wilson Lee · New York : McGraw-Hill · leaf 339
ntrol of the operator at C.The other is the local line and can be called by any subscriber at theexchanges along the line. One plan of operation gives each community automatic exchange aselector switch whose jacks are connected to the toll line (local). Atexchange A level one is connected to the… … Fig. 268.—Two community automatic exchanges with free automatic trunks. level 2 is connected to the local switches. At C it is level 3, at D level 4,and at E level 5, which is connected to the local switches. All the selectors on the toll line are operated simultaneously by the tolloperator in…
Telephone
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