Method of billing charge for used functions of communication device, method of regulating function of communication device, customer center for carrying out the method, and an user system including the communication device

摘要

A key telephone apparatus BT periodically transmits actual-use information including a part of a service function group and use amount of each service function to a customer center CC via a public network PNW. The customer center CC calculates a use charge of each service function based on the received actual-use information, and notifies a user's maintenance personal computer PC of the use charge via Internet INW. Subsequently, confirming payment of the use charge for each service function by a user, the customer center CC creates a license code for changing a flag indicating a regulation state of the service function of the key telephone apparatus BT to transmit the license code to the corresponding key telephone apparatus BT based on the payment.