The migration of serial to Ethernet communications - Why bother?

Serial communications has been the mainstay for communication systems for more than a decade using RS232 and RS485 as the physical layer. However, the Ethernet juggernaut is enticing systems engineers to reevaluate their existing approach to telemetry with the potential benefits of a bigger ‘pipe’. Fortunately, familiar protocols like Modbus and DNP support TCP/IP over Ethernet making the switch relatively easy for greenfield deployments. Retrofitting Ethernet and newer IEDs into existing communications systems including SCADA require supporting a hybrid network of both Ethernet and serial devices. One approach to a hybrid network is serial tunneling through serial servers as described below and includes an example illustrating the benefits of a real implementation.