To save the calling time of an opposite party by controlling the outgoing or incoming calls against an exchange based on the terminal number, the extension number and the voice and/or data communication mode information of a cordless telephone set.

An exchange 1 includes a registered information management part 1a, which registers the calling state of a cordless telephone set and an outgoing/incoming call management part 1b. When a voice terminal B calls a terminal A, the fact that the terminal B is a voice trimanual is recorded on a data base E and also the fact that the terminal A is unable to answer the incoming call sent from the voice terminal is described on a data base F. Then the part 1b can reject its calling, before the incoming processing is carried out to the terminal A with the calling of the terminal B. Therefore, since the calling is rejected, without calling an opposite party when the communication mode is not agree with that of the opposite party, so that an opposite party who will not answer will not be called.