Feature1. Compatible RS-232 and RS-485 standards of EIA/TIA. 2. Automatic data transceiver without external volume control signal (RTS) and three-line (TXD, RXD and GND) communication. 3. Baud rate: 300BPS-115.2KBPS 4. Working current:9-30VDC/350mA 5. A maximum connection of 2 lines of 128 pieces of RS-485 or RS-232 interface devices. 6. Communication distance: 5 KM(9,600BPS). 7. Power indicator