PURPOSE: To improve the utilizing efficiency of the band width of a token bus by making a generalized transmission sequence possible by improving the transmission efficiency and disconnecting a line switching route by means of the last frame in transmission and making the restart of another transmission possible, and then, using a line switching protocol in a token bus protocol. CONSTITUTION: A frame format which is commonly used for both a token bus protocol and a dynamic switch protocol is used and a line switching protocol is superimposed upon the token bus protocol at the time of interlock transmission and data transmission so as to establish a line switching route between a transmission-side node holding a token and a destination node. At the time of initial frame transmission, the line switching route is established between the transmission-side node and destination node by using an ordinary link header. The succeeding data frames have no link header information.