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 56
e bell of the desired tele-phone. If the number called by asubscriber is busy, his receiver willgive forth an intermittent buzzingsound, the same as that used for abusy signal in large manual systems.When through talking he hangs thereceiver on the switch hook and thecircuit changes thus made cause… … Fig. 38.—Desk telephone instrument. 40 A UTOMA TIC TELEPHON Y A small governor, which is geared to the cam shaft, controls the speed atwhich it revolves. The power is furnished by a piano-wire spring whichis rewound each time the subscriber turns the dial. The cam does itswork after the subscribers…
Telephone
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