Communication control unit

A communication control for controlling data transmission and reception between a plurality of terminals and a communication network employing a multi-conjunction architecture via an interface, said communication control unit comprising:

• transmitter/receiver means for transmitting a signal to and for receiving a signal from the communication network, said signal transmitted to and received from the communication network prior to a data communication between the terminal and the communication network comprising at least a destination address portion indicating an address of a destination communication control unit, an originating address portion indicating an address of an originating communication control unit and a signal kind indicating portion indicating whether the signal is a transmission request or an acknowledge signal;
• switch means for enabling signal transmission and reception between a selected one of interfaces and the communication network through said transmitter/receiver means in a first state and for disabling the signal transmission and reception between the selected one of the interfaces and the communication network through said transmitter/receiver means in a second state;
• and
• control means comprising address discriminating means for discriminating whether or not an address indicated by the destination address portion of the signal received from the communication network through said transmitter/receiver means coincides with an address of said communication control unit, signal kind discriminating means for discriminating the kind of the signal received from the communication network through said transmitter/receiver means, selecting means for selecting a desired one of the interfaces coupled to said communication control unit and signal detecting means for detecting whether or not a signal received from the communication network through said transmitter/receiver means is intended for the selected one of the interfaces coupled to said communication control unit based n a discrimination made in said address discriminating means,
• said control means controlling said switch means to the first state only when said address discriminating means discriminates that the two addresses coincide and said signal kind discriminating means discriminating that the signal received is a transmission request signal when receiving the signal from the communication network through said transmitter/receiver means, and controlling said switch means to the first state only when said address discriminating means discriminates that the two addresses coincide and said signal kind discriminating means discriminates that the signal received is an acknowledge signal when transmitting the signal to the communication network through said transmitter/receiver means.