USBGear Dual Port RS-232 USB-to-Serial Plugin Adapter Adds two RS-232 serial ports by connecting to a USB port High speed serial port with the baud rate up to 921.6K bps Full RS-232 modem control signals and hardware/software flow control RS-232 data signals: TxD, RxD, RTS, CTS, DSR, DTR, DCD, RI, GND OS Compatibility:Windows 98, Me, XP, 2000, 2003, CE, Vista, Windows 7, and Windows 8 as well as Linux and Mac OS 10.X