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 267
Fig. 206.—Sender equipment. entire bank as a unit must also be carefully adjusted in position and main-tained there, because the brushes are on long rods which are controlledfrom the bottom. The set of brushes (Fig. 209) consists of four springs; 37 and 38 arethe brushes for the sleeve or third… … Fig. 207.—Selector frame.
Telephone
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