On Windows 7 and Windows 2008 Server, USB-to-serial converters do not work as well as internal serial ports. They are slower and have higher error rates. In some cases, they may not work at all. You should use internal serial ports if possible. Alternately, you can use a third-party virtual serial port program.
If you do use USB-to-serial converters on Windows 7 and 2008 Server, do not use speeds above 115200 bps.
If Windows 7 or Windows 2008 Server does not automatically install your USB-to-serial converter, you will need to download drivers from the converter manufacturer's website. The drivers for the USB-to-serial converters sold by GMCL are available at http://www.vscom.de/616_download.htm.