System and method for communication between nodes of a closed loop local communication path

摘要

In an exemplary embodiment a transmission link coupler is provided at each node. In a transmission mode, the coupler provides a transmission path which transmits incoming messages directly to the node output without any processing step delay. In the decoupling mode of the coupler, the associated data processor still receives messages from the node input, but the direct path from the node input to node output is attenuated. During the sending of messages and responses thereto, the link couplers at the sending and responding nodes are operated so as to prevent the messages from making unattenuated multiple traverses of the loop communications path while also avoiding the occurrence at other nodes of a communications gap which would permit such nodes to interfere with the exchange of messages. The arrangement is such that each node can be implemented with low cost integrated circuitry. No common timing link is required between the nodes. Transmission of requests for control of communication and the actual transmission of desired information between the nodes may all take place via a single channel of the loop communication path.