of this step, is the abolition of the answering-jack to answer the call. In addition to magneto - generator used in calling the central of- the lamps of the answer- fice, and of the sub-station ing-jack s a "pilot-lamp" is battery. used, which glows as long The system which has as any subscriber's… … in the same exchange, the operator electrical engineers and telephone ex- PANEL OF A "B" BOARD IN DETAIL. PANEL OF AN " A " BOARD IN DETAIL perts and would require first taps the edge of the many numbers of the multiple-jack of the sta- Scientific American to tion wanted with the tip of do them…
Patents · Automobile · Apparatus · Artesian · Explosive · Zinc · Great Britain · Horse power · Acetylene gas · Zinc ores · Scientific American · Motor car · High explosive · Building edition · Wrought iron · Gas engine
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