A base station is connected via a public line to a host. The base station transmits a restriction notification signal in response to a request issued from the host. When a wireless terminal apparatus whose subscriber registration operation has already been completed receives the restriction notification signal, the operation mode of this wireless terminal apparatus is brought into a restriction mode. The wireless terminal apparatus returns a disconnect display in the restriction mode in response to a call out request issued from a main board. When a wireless terminal apparatus whose subscriber registration operation has not yet been completed receives the restriction notification signal, this wireless terminal apparatus executes a subscriber registration sequence between the wireless terminal apparatus and the base station.