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 391
sstation. A very convenient and commonly used type of machine consists of asmall (0.1 h.p.) direct-current motor designed to run at a speed of ap-proximately 400 revolutions per minute. On the shaft of this machineis mounted a large fiber cam, similar to that used on a telephone callingdevice,… … Fig. 292.-—A view showing the wire chiefs desk in an automatic central office. pair of springs may be adjusted to give an impulse of the same characteras that given by the calling device. The set has flexible cords ending in a clip and terminals. The clip isattached to the negative battery pole.…
Telephone
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