An object of the invention is to enable the user, in the case of a wired telephone, to check an incoming call even when the user is not present near the telephone and, regardless of the type of the telephone, enable the user to check calling party information when a call arrives. A gateway apparatus associates a PDA with a NET telephone connected to a LAN and, upon receiving an incoming call to the NET telephone, notifies the PDA of the calling telephone number received from a local exchange. When the incoming call notification is received from the gateway apparatus, the PDA causes a ringing tone to sound and displays the received calling telephone number. Further, based on the calling telephone number, the PDA searches telephone directory data stored therein and displays calling party information such as the caller's name.