TY - JOUR
AB - To avoid the incorrect recording of callers' numbers in a trunk exchange associated with an automatic telephone area, various expedients have been adopted, including the reversion of a certain percentage of originating calls to the use of an audible tone. The supersonic signal method is described in a paper by W. K. Brasher and B. P. Moss (J. Inst. Elect. Eng., July). It was evolved for Palestine, a country in which the use of a number of languages made the problem more acute. It is usual to check a certain number of demand calls either by establishing a second connexion to the subscriber's line, independent of the first, or by ’reverting’ the call, that is, recording the particulars of the required number and informing the caller that he will be rung. Both methods lead to delays. Messrs. Brasher and Moss give a full description with diagrams of the method, which is being evolved in Palestine and is now being installed. Demand positions are served by a 20 kc./sec. oscillator, the output of which can be connected to the operator's telephone circuit of each position. When the demand operator has received the particulars of the wanted and calling subscribers, she passes the call to the distant exchange and moves a dialling plug suitably. The basic principle of the use of a supersonic signal in an automatic telephone exchange has been proved by test to be a practical scheme, no disturbing effect on other circuits having been noticed in a 5,000-line exchange.
TI - Verifying Telephone Subscribers' Numbers
JF - Nature
DO - 10.1038/146300a0
DA - 1940-08-31
UR - https://www.deepdyve.com/lp/springer-journals/verifying-telephone-subscribers-numbers-QVd44LBb52
SP - 300
EP - 300
VL - 146
IS - 3696
DP - DeepDyve
ER -