The practical telephone handbook and guide to the telephonic exchange (1906) (14755799962)

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

Text Appearing Before Image:

-mitter is made through aspring which normallypresses on a metal piecefixed on the ebonite rim ofthe case, but when the caseis revolved, so that thefunnel is out of position,the contact is broken, andthe transmitter current iscut off. A late form of breastplatetransmitter made by theWestern Electric Co. isshown in Fig. 75. A solid-back transmitter is em-ployed, to which is fitted along ebonite mouth-piece,provided with a universal ball-joint, so that it may be adjusted or swung round outof the way when not required. This instrument is adoptedin common battery exchanges, and is very powerful. It is usual to allot a particular breastplate set to eachoperator in an exchange, the operator being responsible forits safe-keeping and cleanliness. Transmitter-Testing.—This is usually done through an actuallong line or sometimes through an artificially made up line.The latter is made up of a number of coils of wire, each having aresistance representing a certain length of line and a number of

Text Appearing After Image:

Fig. 74 84 PRACTICAL TELEPHONE HANDBOOK condensers also of a capacity equal to that of the same sectionof line, the condensers being connected as branches to the coils,which are joined in series (as shown in Fig. 76) so that the whole

hands free telephone operators the practical telephone handbook and guide to the telephonic exchange 1906 book illustrations history of technology electric power telephone transmitter radio images from internet archive

1906

Northeastern University, Snell Library

http://commons.wikimedia.org/

public domain