American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 459
lic relay is then caused to operate the register. The central office is alsoequipped with a telephone set which is tapped on to the metallic circuit, as shown,and is prevented from grounding that circuit by the use of the condenser c, in themanner described in Chapter XXII. (Simultaneous Telegraphy… … WILDER BURGLAR ALARM TELEGRAPH SYSTEI T, in CO, is an instrument termed a testometer. It controls a special, separatecircuit running parallel with the alarm circuit and enters all the buildings of the sys-tem. By aid of the testometer and apparatus with which the protected building isequipped, an…
Telegraph
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