| 摘要 |
PURPOSE:To obtain a data communication system suited to each application with simple constitution, by applying two different access systems to a transmission medium and controlling these access systems by giving priority levels of a network. CONSTITUTION:Transmitting/receiving stations 2-6 are connected with taps to a medium 1, and terminals 7-11 are connected to these stations, respectively. A pass type transmitting/receiving network is formed to enable all transmitting/ receiving stations to receive the signals transmitted from the stations 2-6 via the medium 1. Transmittig/receiving stations A-E include a station of token passing system which receives access to the network in response to the transmitting right added with a packet, a station of random access RA system which receives access again in a lapse of a prescribed time in case the first access fails, and a station which includes both access systems. With the TP system, access is given to the network having the highest priority level among plural networks, and the station of RA system gives access to the network in case the station of the next priority level has no packet to transmit. |
