PURPOSE: To preferentially connect a line to a user, who eagerly desires the connection of the line, while increasing charges by setting the connection request frequency of a call with a prescribed ratio corresponding to the charges selected by a caller and controlling call connection based on the connection request frequency.

CONSTITUTION: Assuming that the plural subscriber numbers of callees are provided corresponding to the plural charges of charging system concerning preferential connection, the user can select any desired reception number by selecting the subscriber number of the callee corresponding to the charges, dialing that number and originating a call. When the call is received, a ring back tone device 105 stores it in a memory. This memory constitutes the queue in the order of receiving the respective calls for each reception number. When the user originates the call, it is connected to an incoming line 101 and connected through a converter 102 to the ring back tone device 105. In this case, the ring back tone device 105 controls call connection based on the connection request frequency with prescribed method.