Telegraph engineering : a manual for practicing telegraph engineers and engineering students (1922)
Hausmann, Erich, 1886- · New York : D. Van Nostrand Company · leaf 154
IC 139 Changes in these normal conditions are effected by single or double flexible conductors or patching cords having plug terminals which fit into the jacks. Fig. 3 shows the type of pin-jacks and plugs now extensively used on telegraph and telephone switchboards. Main Switchboards. —All line… … Fig. 3. BU9Y TEST KNOBS .MAIN LINE fiENBRATOR ^RESISTANCELAMP
Telegraph
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