Worldwide energy metering networks use differential data transmission based on RS-485 technology to span long distance data links. To overcome large ground potential differences between remote bus nodes, transceivers are galvanically isolated from their node circuitry. An e-meter network is a master-slave system with a host processor (master) that is located in a control center. The master addresses multiple slave nodes which are located in the end user premises along the bus. A single network typically comprises up to 60 nodes, making the potential for cross-wire faults of the twisted-pair bus cable during installation rather high. To assure reliable data transmission, modern transceivers apply automatic polarity correction (POLCOR) of the bus signal polarity.
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