... 20KMCommunication Standard Accord EIA RS-232, RS-485, RS-422 standard RS-232 signalIN, OUT, GND RS-485 signalD+, D-, GNDRS ... mode 1310nm Electricity port transmissionRS-232 port 15M, RS-485/422 port 1200M Optic port transmission Multi- ... mode 2KM, signal-mode 20KM Loading RS-485/422 port Support 32 port loop enviroment ... Date:2012-04-24 04:33:09 RS-232/485/422 serial optic fiber modem