The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 268
andplug. The relay J is used in place of the 40-ohm shunt to the 12-voltclearing lamp and serves to prevent the called-for subscriberbeing rung unless the junction line connection is properly com-pleted to the calling subscriber, as the connecting cord contactsare only completed when this relay is… … 242 PRACTICAL TELEPHONE HANDBOOK The upper part of the diagram shows the connections offour order wires to the operators telephone, the break-jacksto which they are connected being for use only when any ofthe order wires become faulty, the insertion of a plug cuttingoff the faulty wire. A switch is…
Telephone
Internet Archive · Northeastern University Library · Public Domain Mark 1.0. Free to use for anything.
