My PC Doesn't Have a COM Port

Started by Andy Ayre, July 10, 2009, 10:00:02 AM

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Andy Ayre

It is becoming increasingly common for PCs to not be provided with a COM port, especially laptops/notebooks.

It is possible to buy cables that convert USB to a COM port. When connected these cables act as a virtual COM port and from the point of view of software running on the PC they are a real COM port.


  • Go to Control Panel -> System -> Hardware -> Device Manager
  • Expand the Ports list to see your COM ports
  • Connect the cable and see which new COM port appears
  • Use that COM port number in Flash Magic

However note that some of these cables don't appear to work well when used for reprogramming microcontrollers. The cause is unknown but is probably related to the timing of data on the USB side. It may be PC dependent or cable dependent. If you find that you can't program the device then try other cables.

In general we recommend using a PC with a built-in COM port or getting a PCI card with COM ports, until the situation with the USB to COM port cables improves.
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