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 178
and Plugs.—A reproduction of a photograph of asingle position switchboard of this type with a capacity of about 60lines is given in Fig. 157. This type of board is commonly equippedwith regular cord circuits for interconnecting local lines and for connect-ing them to the trunks; and also with two… … 162 AUTOMATIC TELEPHONY the toll board or from the switches at the central office. This board hasthe customary supervisory and night-alarm circuits. A general diagrammatic scheme of the circuits is shown in Fig. 158.The line circuit is equipped with relay and lamp signals. The regularcord circuit…
Telephone
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