The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 319
-.;• Fig. 295.—Intermediate Distributing Frame and Relay Racks which, in large exchanges, are generally fitted apart from thesubscribers sections. From the vertical side of the intermediate frame 84 wirecables are carried to answering-jacks and calling lamps of thevarious subscribers sections of…
Telephone
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