The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 530
e operator. A boardmade up of these sections is employed in exchanges where butlittle junction or trunk work is required. As the rate ofcalling where such a board is needed is generally small and * See also a very full account by J. W. Turner in th? Post OfficeEngineers Journal for January 1910.… … Fig. 465.—Section of No. 9 Switch-Board the refinements in detail necessary with the larger switch-boards. Line Connections.—Fig. 466 shows the full connections ofthe board. The jacks are 5-point break ones multipled at 502 PRACTICAL TELEPHONE HANDBOOK
Telephone
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