Ring transmission network for interfacing control functions between master and slave devices

摘要

A ring network is comprised of slave devices (96) (98), (100) and (102) that are interconnected on a ring network. The slave device (96) is interfaced with a test/maintenance controller (120) through a serial transmission line (106). The slave device (96) is interfaced with the slave device (98) through a serial transmission line (108). The slave device (98) is interfaced with the slave device (100) through a line (110) and the slave device (102) is interfaced with the slave device (100) through a line (112) with the slave device (102) being interfaced with the controller (120) through a line (114). A clock is generated by the controller (120) and transmitted to each of the slave devices through a node (1188) to provide an asynchronous clock with respect thereto. Each of the slave devices has an internal synchronizing circuit (130) for synchronizing the internal operation of the devices with respect to the controller (120). In addition, a data line select circuit (121) is provided to determine direction of transmission on the bus. The controller selects the position of the devices on the bus by transmitting a unique identifier which is recognized by a slave device as a select signal therefor as a function of its relative position on the bus with respect to the point from which the data was transmitted. The controller (120) can transmit from either direction on the bus and receive data from either direction.