Protected facility for amending stored data at exchange - requires code number and call made from authorised number before use

摘要

Customer data stored by the central controller of a telephone exchange can be amended by dialling the exchange, dialling a code number, and then entering the new data by further dialling. Since this facility is liable to misuse if the code number becomes known, it use is limited to calls from authorised numbers, e.g. in central administration. The procedure is that the caller rings the exchange, gives the code number and then hangs up. The exchange central controller checks the code number, reads out the associated stored telephone number, finds a line and causes that number to be dialled. When the caller answers, he can then enter the amendment. The facility is protected by the fact that the central controller only accepts amendments on calls it has originated. The function of the code number is merely to initiate the procedure.