A telephone number memory circuit is provided in which data for determining the display of a call on a selected one of call receiving modules depending on the telephone number of a caller is stored. As the call is received from the service network, the telephone number of a caller is detected by a telephone number detecting circuit and transferred to a control module. The control module compares the detected telephone number with the data saved in the telephone number memory circuit to determine the display of the call on the selected one of a call display of a master unit, a call display of a first sub unit, and a call display of a second sub unit and directs the selected call display to indicate that the call is received. In a telephone system including a number of telephone terminals, a calling apparatus directs a selected one of the telephone terminals to display the call depending on the telephone number of a caller.