This device will convert USB port on PC to full-duplex RS-422 or half-duplex RS-485 signal. 

Specification:

• Compatible with USB 2.0, hot plug-play
• Compatible with TIA/EIA RS-485/RS422
• Baud Rate: 300bps~921.6kbps adaptive.
• Can support up to 32 RS-422 or RS495 devices.
• Powered by USB host
• ESD: 15kV contact
• Enviroment: -25 degree C to 70 degree C, humidity 5% to 95%
• OS: Windows 98/98SE/ME/2000/20003/2008/XP/Vista/7, Linux, MAC, WinCE