The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 177
strip ofebonite, and are kept inposition by thin strips ofebonite, which are fittedin recesses cut in thesides of the springs, andscrewed down to theblock, as shown. Thefifth spring of each jackis connected to a brass socket, shown by dotted lines, fittedinto another strip of ebonite (11J inches… … S POIWT BREAK JACK Fig. 169.—Scale \ SWITCH-BOARD APPARATUS 153 When a plug is inserted in a jack the two outer springsare pressed away from the two shorter inner springs, and thusbreak contact. Fig. 170 gives a view of a strip of ten 4-point jacks con- ajfU Mi
Telephone
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