COMMUNICATION APPARATUS WITH THE FACILITY OF REPEATING THE GLOBAL BUS IN RS-485

摘要

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an all-electronic exchange, comprising a first connector and one first communication circuit for connecting a first communication device used for operation of the all-electronic exchange to a global bus of RS485 type. A second communication device comprising: a second connector connected with a first communication circuit and the global bus; A third connector connected to second communication devices and the global bus; A second and third communication circuit connected with the second and third connectors via a global bus, the second and third communication circuits being configured for redundancy for communication with the first and second communication devices, the communication circuit comprising: Bus control circuitry for generating and transmitting data, control signals, and clock related information to and from a communication device, and for receiving data from the first and second communication devices; A reception driving circuit which receives data transmitted through the third connector and transmits the data to the bus control circuit; A transmission control circuit for receiving a clock related information transmitted through the third connector and outputting a signal informing transmission of clock reception data transmitted to the bus control circuit; A transmission drive circuit controlled by the transmission control circuit to transmit data from the bus control circuit and a signal indicative of the occupation of the global bus to the third connector; A clock transmission circuit for transmitting clock related information of the bus control circuit to a third connector; A redundant mast control circuit for controlling masts and slaves of the second and third communication circuits of the redundant structure; A clock relay transmitting circuit which is controlled by a redundant mast control circuit and relays clock related information output from a bus control circuit to the second connector; A relay transmission circuit, controlled by a redundant mast control circuit, for relay transmission so that the output signal of the transmission drive circuit can be output through the second connector; And a relay receiving circuit which is controlled by a redundant mast control circuit and a relay transmitting circuit to relay and receive data applied through the second connector to the reception driving circuit, and controls the transmission circuit to be driven when the relay reception is not performed.