. The practical telephone handbook and guide to the telephonic exchange . ^8 Fig. 206 speaking current is supplied from that battery which isconnected to the connecting cord used for joining the lines,the battery connected to the second line being an extension line is connected through to the main exchangethe cord in connection withthe junction line is used formaking the connection, andthe speaking current for theextension instrument is sup-plied from the central battery. Fig. 207 is an outlinesketch of a 6-line board, withthe ringing generator r gscrewed to the side. Theboard
. The practical telephone handbook and guide to the telephonic exchange . ^8 Fig. 206 speaking current is supplied from that battery which isconnected to the connecting cord used for joining the lines,the battery connected to the second line being an extension line is connected through to the main exchangethe cord in connection withthe junction line is used formaking the connection, andthe speaking current for theextension instrument is sup-plied from the central battery. Fig. 207 is an outlinesketch 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 service instrument jacks J is fitted below the otherjacks. The main exchange is signalled by inserting the service plug into the junction-jack(or vice versa) and raising the receiver. Cordless and Plugless Boards.—Fig. 208 shows a very OOO[ 0 OO I G O O 1 ; 1 G G O 1 0 Fig. 207 i8o PRACTICAL TELEPHONE HANDBOOK. SMALL SWITCH-BOARDS iSi convenient type of small switch-board used for privatebranch extensions. It is intended to stand on a desk or a table.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjecttelephone, bookyear19
