Station arrangement in data transmission network

Claim 1

A station arrangement including a plurality of terminal controllers each connected with a user unit, and a central controller connected through an intra-system bus with said terminal controllers and also connected to an inter-system bus, for implementing data transmission through said inter-system bus with one or more other stations connected commonly on said inter-system bus; each of said terminal controllers comprising: (a) means for forming data sent from said user unit into a data packet: (b) first transmission means for transmitting said data packet onto said intra-system bus in accordance with network protocol conformable to the procedure for layer 3 or layer 4 of the seven layers of the Open Systems Interconnection (OSI) model (IS 7498) stated by the International Organization for Standardization (ISO); (c) means for receiving a data packet sent over said intra-system bus from another station, in accordance with the network protocol; (d) means for reforming the data packet received by said reception means to have a format suitable for said user unit; and (e) second transmission means for transmitting the reformed data to said user unit; said central controller comprising: (f) bus access means for transmitting the data packet from said first transmission means onto said inter-system bus by a procedure conformable to layer 1 and layer 2 of the seven layers of the OSI model and (g) means for taking in a data packet destined to the self station from said inter-system bus and sending the data packet onto said intra-system bus.