JPH05236076

PURPOSE:To automatically select the optimum duration of a call by setting the time closest to the average duration of calls. CONSTITUTION:A CPUa measures an elapsed time T1 updates count C of a counter counting the number of telephone calls at the end of the phone call, adds T1 to total time T, determining the average duration of a call Z by T/C. Then, call setting time Y (for example, three minutes in a charging table) closest to the Z is selected from among the selectably call setting time in the specifications. The selected setting time Y is sent form the CPUa to a CPUb. Thus, the CPUb operates by taking the setting time as Y at the next dialing and the troublesome operation of a user selecting the setting time by himself each time when a user makes a call, can be eliminated. The optimum setting time is selected according to the average duration of calls and a person in charge of trunk line network providing the most inexpensive charge for a telephone call can be selected.