GB273015A - Improvements in or relating to telephone systems - Google Patents

Abstract

273,015. Automatic Telephone Manufacturing Co., Ltd.., and Mercer R. March 26, 1926. Automatic exchange systems.-In a network in which two exchange letters only are required to differentiate between all the exchanges, subscribers or operators set up three letters, but one, preierably the second, is suppressed, or routed away from the normal receiving apparatus. In calls from substations the suppression is preferably effected at the register translator, but in the case of operators' impulse senders with a row of keys for each letter, the row corresponding to the letter to be suppressed is left dead, or in a sender of the kind described in Specification 220,774, one of the keypressing operations is rendered ineffective. In systems comprising four and three letter networks, the second letter at three digit exchanges may be suppressed at the A digit switch and used to energize the switching relay. Fig. 1 shows a sequence switch S for steering the incoming digits to the registers of a register translator of the usual kind, provided with means whereby by a simple manual operation it may be adapted either to receive and record two exchange letters or to receive three and record only the first and third. In the first case a stop AM is so adjusted that the normal position of the wipers 106, 107 of the switch S is on the second contact set, the first set being ineffective, whilst terminals 5, 1 and 6, 3 of a terminal block TB are jumpered so that the first and second digits are directed over conductors 121, 122 respectively to the vertical and rotary magnets of the exchange register. In the second case the stop AM is adjusted to make the first contact set the normal position, and terminals 1, 4 and 2, 5 and 3, 6 of the block TB are jumpered so that the first and third digits are directed to the exchange register and the second digit is routed away over a resistance 7. In a modification in which the switch S is a continuous motion one with an additional restoring wiper, the first four contacts engaged by this wiper are connected to extra terminals provided on the block TB, and the jumpering between these terminals may be modified to cause the switch to restore to its first or second position. Specifications 194,580, 220,923 and 233,007 also are referred to.