File:The practical telephone handbook and guide to the telephonic exchange (1906) (14753820484).jpg

Identifier: practicaltelepho00pool (find matches)
Title: The practical telephone handbook and guide to the telephonic exchange
Year: 1906 (1900s)
Authors: Poole, Joseph
Subjects: Telephone
Publisher: New York, Macmillan Co.
Contributing Library: Northeastern University, Snell Library
Digitizing Sponsor: Boston Library Consortium Member Libraries

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Text Appearing Before Image:
ORDER-WIREKEYS. ORDER-WIRE KEYS Fig. 249.— Scale £ may more readily make their way between the others, andthus prevent crossing and entanglement. Another method of providing for a long cord is to build theswitch-board on a false floor, raised about 1 foot or more abovethe ordinary floor, an opening being left for the pulley weightsto pass through. This construction adds 2 feet, or doublethe height of the false floor, to the practical length of the cords. Plug Shelf.—To prevent damage and noise caused by thefalling of the plugs on the plug shelf, the face of the latter iscovered with sole leather about J inch thick. The opal
Text Appearing After Image:
*• ••••••♦•♦«#♦•• ,»••,»» feSs^asaSa^ COMMON BATTERY MULTIPLE SWITCH-BOARDS 229 caps of the supervisory lamps are also protected from damageby perforated metal caps. Operators Jacks.—On the under side of the key-board twoinstrument jacks are fitted to each operators position—one toconnect her own telephone set, and the other so that a secondset may be connected for a learner or a supervisor. All the switches, etc., fitted under the key-board are boxedin, so as to render them dust-proof, and each key-board ishinged at the back, so that it may be raised for inspection ofthe fittings, etc. Jack-Field.—The front of the switch-board, where the jacks,calling lamps, etc., are fitted, is called the jack-field.There arc eight panels in each section of the Barnsburyboard, and at the bottom of each panel is fitted the pilotlamp, which is lit each time any calling lamp in that panelglows. The calling lamps and answering jacks arefitted at the lower part in

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