An object of the present invention is to control incoming data to be received
by an appropriate communication destination by using a main device to monitor a
traffic state of a wireless LAN and a user login state. A main device (1)
for performing call control call control of wireless telephone (8, 8) determines
a transmission destination (transfer destination) of a call received from, for
example, a traffic state of the wireless-LAN base station (2, 3) or a login
state of the wireless telephone, and transmits data to, for example, a public network
(6), a local-area network, or an IP telephone network. In addition, the
main device (1) preliminarily transmits data-reception notifying mail to
a reception destination to enable a user to select a data-receiving method.
