... star, daisy chain topologies networks.Specification:Electrical interfaceRS232/422/485 interface:RS232 speed: 0-115200bps;RS232 support for RXD, TXD, GND ... 3-line approach to work;RS422 support for RX-, RX +, TX-, TX ... um,9/125um,10/125umTransmission distance: MM 2Km,SM 20KmFiber interface type: ST/SC/FC (optional), ST StandardRelayContact rating:DC30V ...