Telegraph engineering : a manual for practicing telegraph engineers and engineering students (1922)
Hausmann, Erich, 1886- · New York : D. Van Nostrand Company · leaf 218
ons will now be considered. At a manual central station, each signal-box circuit ter-minates in a visual drop and a relay; the latter actuates MUNICIPAL TELEGRAPHS 203 a bell and one pen of a multiple-pen register, Fig. 2. In-coming alarms are received by one or more operators,who are on duty at… … Fig. 8. grouped on several circuits, it is necessary to transmitthe signal over all apparatus-house circuits simultaneously.This is accomplished by fire-alarm transmitters, threetypes of which are illustrated in Figs. 8, 9 and 10. Fig. 8 represents a spring-driven detachable signal-wheel…
Telegraph
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