Subscriber information shifting technique for a private exchange

Abstract

In order to shift a subscriber's extension telephone from one port to another in a private exchange having a subscriber information shifting button on each extension telephone, a subscriber information shifting technique includes: determining whether the telephone moved to another port is off-hook, generating a dial tone and sensing the operation of the subscriber information shifting button on the telephone; determining whether a subscriber class is authorized to modify exchange programming when the operation of the subscriber information shifting button has been sensed; generating a switchover tone and sensing a subscriber's extension number and identification number when the subscriber class is authorised, determining whether there is an extension number for the another port after sensing the subscriber's extension number and identification number, determining whether the identification number is valid when there is an extension number; changing the subscriber information when the identification number is right, and generating a confirming tone and sensing an on-hook condition after changing the subscriber information.