GB191126830A - Improved Circuit Systems for Operating between Manual and Automatic Telephone Exchanges. - Google Patents

Abstract

26,830. Siemens Bros. & Co., [Siemens & Halske Akt.-Ges.]. Nov. 30. Semi-automatic exchange systems.-Relates to a method of indicating to a manual junction operator a disengaged junction line leading to an automatic exchange. A signal lamp is provided for each junction line at each operator's position as usual, but instead of arranging that all the lamps of all the disengaged junction lines shall light up, a rotary selective switch W for each group of lines closes the signal circuit of only one disengaged line at a time. The switch W is rotated by a magnet D controlled by a relay p connected to the wiper sp which moves over contacts connected to the test leads of the junction lines L<1> ... L<x>. When the wiper sp engages an idle junction line L<x>, the relay p is energized, cutting off the magnet D and closing a circuit over the wiper sl for the corresponding signal lamps l<x>. If the selector GW is moved from its zero position, thereby opening the contact k, or if the line is defective or the fuse Si broken, or if the line has been engaged from the outgoing end, thereby energizing a relay C, the relay p is deenergized, and the magnet D rotates the switch W until an idle line is found. Keys T', T<2> may be provided at each operator's position, so that the signal lamps light up only when these keys are depressed.