... electrical interface. The modems provide fiber optic connection in point to point, star, daisy chain topologies networks.SpecificationElectrical interfaceRS232/422/485 ... -115200bps;RS232 support for RXD, TXD, GND 3-line approach to work;RS422 support for RX-, RX +, TX-, TX + full-duplex mode ... ;RS485 support for A, B half-duplex mode;RS422/485 Rate: 0-2M (optional ...