Cyclopedia of Telephony and Telegraphy, Vol. 2 / A General Reference Work on Telephony, etc. etc.

by American School of Correspondence

Fig. 324. Strip of Relays
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A bank of line relays especially adapted for small common-battery switchboards as made by the Dean Company, is shown in Fig. 325.

Fig. 325. Bank of Relays
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Jacks. The jacks in common-battery switchboards are almost always mounted in groups of ten or twenty, the arrangement being similar to that discussed in connection with lamp strips. Ordinarily in common-battery work the jack is provided with two inner contacts so as to cut off both sides of the signaling circuit when the operator plugs in. A strip of such jacks is shown in Fig. 326.

Fig. 326. Strip of Cut-Off Jacks
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Ringing and listening keys for simple common-battery switchboards differ in no essential respect from those employed in magneto boards.