RS485 is a standard defined for digital communications effectively over long distances and in electrically noisy environments.

This RS485 Converter Adapter incorporate a MAX485 transceiver chip, powered by USB port with fully compliant USB 2.0 standard; backward compatible with USB1.1

Support System: Windows XP , Vista, Windows 7/8 , Linux , MacOS , and WinCE5.0 drive Supports baud rate range : 75bps - 115200bps , up to 6Mbps Supports Plug , Play and hot-swap ( USB side)

Communication distance up to 1.2KM, with anti-jamming performance of industrial site.

All kinds with RS485 port device parameter settings , data communication Short distance , such as parameter settings of the computer peripheral equipment , the use of common data lines can be  A and A port of the device when the wiring is connected , B and device B connected . Some devices D + A and D, - B

Documents:

CH340 Datasheet 

USB RS438 Windows XP 32 bit Driver 

USB RS438 Windows XP 64 bit Driver