The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 205
linesketch of a 6-line board, withthe ringing generator r gscrewed to the side. Theboard is similar to that shownin Fig. 197, and is operated ina somewhat similar manner.The service instrument jacks J is fitted below the otherjacks. The main exchange is signalled by inserting the service plug into… … SMALL SWITCH-BOARDS iSi convenient type of small switch-board used for C.B. privatebranch extensions. It is intended to stand on a desk or a table.
Telephone
Internet Archive · Northeastern University Library · Public Domain Mark 1.0. Free to use for anything.
