1.Conform to PCI specification version 2.1; 2.Conform to the RS485 telecom standard; 3.Support auto shift between RS485 and RS422; The transmission distance of RS422/485 can be up to 1200m (9600BPS); 4.The transmission speed of each serial port is 300~115200bps; 5.Support piont to multi-point; Each port can connect 32 RS422/485 devices; 6.Built-in optoelectronic isolation DC-DC transformer isolates external pressure effectively; 7.Extra TVS can prevent signals from crosstalk and improve the telecom stabilization; 8.Static grade class 3>16kVto protect the device from human electrostatic hazards.