The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 287
or a total of 42 positions. Each section of the boardis made up of three panels, as shown in Fig. 268. During thebusiest part of the day each operator attends to 5 trunk lines,but provision is made so that all these trunks lines may be concentrated on to certain special sections of the board,… … TRUNK-LINE EXCHANGES 261 trunk lines, a further number, up to 20, terminated onthem. Fig. 269 gives the connections of a trunk line from the chiefLondon trunk exchange to a provincial trunk exchange. Itwill be seen that the connections at the London end are some-what complicated, this being…
Telephone
Internet Archive · Northeastern University Library · Public Domain Mark 1.0. Free to use for anything.
