The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 194
screened from the light of the comparatively brilliantlamps used for illuminating the switch - board, and thisespecially applies to the clearing lamps fitted on the cordshelves. To achieve this purpose the illuminating lamps,which are in a row at the top and front of the switch-board, are provided… … Fig. 194a.—Slow-Acting Relay Slow-Acting Relay.—When a relay is required to be operatedby an alternating current, as in certain cases of party-lineworking, trouble is experienced with ordinary relays owing tothe chattering of their armatures. In such cases a slow-acting relay, such as shown in Fig.…
Telephone
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