Abstract: A terminal control apparatus1 for causing various terminal devices to perform appropriate operations. The terminal control apparatus comprises a communication section 11, a control section 12, and a data-storing section 13. The communication section 11 accomplishes communication with a terminal device 2. The control section 12 controls the terminal device 2. The terminal device 3 comprises a communication section 21, a control section 22, and a terminal section 23. The communication section 21 achieves communication with the terminal control apparatus 1. The control section 22 transmits terminal information to the terminal control apparatus 1. The terminal information represents the type and capacity of the terminal device 2. The terminal control apparatus 1 performs terminal control functions in accordance with the terminal information. The control section 22 controls the terminal section 23 in accordance with the terminal control functions the apparatus 1 has performed.

Abstract: This invention relates to provide a communication network system, a gateway, and a data communication method, in which the gateway has an advanced functionality. A person who issues an access request can retrieve a desired access destination easily by the following configuration: functions of routing information providing and authentication processing are added to a gateway that performs protocol conversion between two different communication networks; when an access request is issued from a public communication network such as Internet to a terminal in a local (private) communication network connected to the gateway, a request terminal is authenticated to enable prevention of unauthorized data writing and reading; and an access request user who succeeded in the authentication is provided with an active terminal list comprising accessible terminal information, or with a user condition table.