PURPOSE: To automatically guide a revised number when an incoming call is using an old subscriber number, by forming new or abolished number guide information for an electronic exchange provided with an automatic pevise number function for subscriber numbers, into a talkie.

CONSTITUTION: In an electronic exchange having an automatic number revision function for subscriber numbers using terminal devices such as typewriters, revised number information transferred through an inter-processor information transfer bus PTB from a central controller CC is edited into a revised number guide talkie, and the guide talkie is transmitted from a synthesized sound generator SCSE with a call tone reception. Thus, the maintenance personnel can automatically perform revised number guide to incoming calls of old subscriber telephone numbers only with the operation of the revised and abolished numbers of the subscriber number from terminals such as typewriters.