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PC serial (RS-232) port support and setup

Posted: 03 Feb 2014, 14:51
by Closetalk Support
Modern PC:s do not have built-in serial (RS-232) ports anymore. There are two ways to get serial port support on a modern PC:
  • By using an USB-RS232 adapter. This is usually the only way for laptops although there are PC-card adapters available, most often very expensive
  • By using a PCI or PCI-express serial port adapter card. This is the best and recommended way for desktop computers although USB adapters also work with desktops
USB-RS232 adapters can ususally be found at well-supplied computer part retailers. PCI adapter cards commonly requires a more specialized dealer/retailer.

A faulty installed adapter and operating system drivers is a common installation problem, here follows a few recommendations:
  • There are a lot of low quality "no-name" adapter manufacturers on the market, always choose an "established" manufacturer for the adapter. To check if a manfufacturer is "established", visit their web site and see if they update their drivers regularely, that is usually a sign of quality
  • Only use an adapter that has support and drivers for the exact operating system version, i.e. do not use Windows 7 or 8 drivers for Windows 8.1
  • Always follow the installation instructions carefully. A common mistake is to connect the USB adapter before installing the drivers, this may result in Windows rejecting the adapter which must be corrected manually using Windows Device Manager
  • Keep the drivers updated. This is especially important if the operating system has been upgraded, e.g. Vista to Windows 8, or is new (Windows 8.1)
  • With Windows 8 and especially Windows 8.1, make very sure that the adapter is still supported and has updated drivers! As an example, older ATEN USB-RS232 adapters are supported on Windows 8 but not on 8.1
  • After installation and before using the serial port, open the Windows Device Manager to verify that the adapter has been installed correctly and to note what COM-port number it was assigned, this is important for the Close Talk PC software configuration
By following these recommendations most problems with serial ports will be eliminated.