PURPOSE: To facilitate the payment of a talking charge by devising the titled system such that extensions accommodated in a PBX at dwelling units or the like pre-pay required charge so that outgoing connection is attained and incoming connection as well as outgoing connection are disabled if the pre-paid money is used out.

CONSTITUTION: A telephone user So of a dwelling unit pays cash to a cash deposit machine as the pre-paid money for the telephone utility charge. A cash deposit machine 4 informs the pre-payment of the user to a center equipment 3 of the swelling units, where the pre-payment is recorded. The cash deposit machine 4 gives a receipt to the user So. The user So can use telephone till the pre-payment is used out and cannot make a phone call if the pre-payment money is used out. The center equipment 3 monitors and controls it. When the user So makes calls through the center equipment 3 to a telephone station, a talking bill in matching with the call is sent to the manager of the dwelling units from the telephone station.