Twentieth century manual of railway and commercial telegraphy (1905)
Meyer, Frederic Louis, b. 1875 · Chicago, New York, Rand, McNally & Company · leaf 34
is inserted in any ofthe si)ring-jacks on the board. The insertion ofihe plug raises a spring lever, thereby breaking themetallic connections between the jaws of the jackand allowing the circuit to go through the instru-ments wliicli are connected through the cord. MANUAL OF TELEGRAPHY. 81 When the… … Fig. 23. Section of a Switch-Board,showing spring-jack and phig. For further instructions on switchboards seeAppendix A.
Telegraph
Internet Archive · Northeastern University Library · Public Domain Mark 1.0. Free to use for anything.
