PURPOSE: To decrease the complaint in charge and to discriminate abnormal charging, by setting an estimated amount of money for the 1st call from a subscriber, making detailed charging only on calls exceeding the amount of money and informing the result to the subscriber.

CONSTITUTION: When a calling subscriber dials a specific number for the registration of this service, a central controller CPU registrates the subscriber in subscriber data as a charge instantaneous informing subscriber. The calling subscriber registrates the minimum charge desired for instantaneous information with dialing succeedingly. This charge is registrated the same as above. A CPU calculates the number of calls at the end of call. The registration of this service is recognized from the subscriber data, the charge is calculated and when the charge is calculated and the charge exceeds the registration value, the telephone number and charge of the calling subscriber are transferred to a board for instantaneous information and the recording of the excess of the registrated charge is recorded on a recorder. The board connects subscribes in the path of an instantaneous information board trunk OPT with the transferred calling number and informs the charge.