The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 88
of the tabs of theconnecting cord coming into contact by the turning of thebinding posts, a thick strip of ebonite is fixed between theposts by a central screw. The diaphragm used in this instrument is of tinned iron,about 10 mils thick and 212 inches diameter. The Kellogg Receiver *—This receiver… … Fig. 48.—Scale £ ebonite case has a screw cut to correspond. The magnet isscrewed in from the mouth of the case, and as the lengthbetween the fixing point and the pole ends is small the differenceof expansion has little effect. This instrument is provided witha small ebonite cap, which screws over…
Telephone
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