Hawkins electrical guide ... : questions, answers & illustrations : a progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications ; a practical treatise (1914)
Hawkins, N. (Nehemiah), 1833-1928 · New York : T. Audel & Co. · leaf 72
special trunk line connecting with theB board of the other exchange. Every B board carries the trunk lineswhich originate at the most important switchboard, the A board. The A operator automatically connects with the B operator bydepressing an order wire button, and repeats the calling… … OVCR
Electrical engineering
Internet Archive · Brigham Young University · Public Domain Mark 1.0. Free to use for anything.
