Establishing a serial port or COM port on PCs for USB-to-serial adapters

by Michael Wright, K6MFW, Jan 25, 2013
mfwright @ batnet.com

Many people with 2-way radios, scanners, or whatever device which uses RS-232 serial data communication, and like many others I have a modern laptop with no serial port. Serial ports on laptops were common years ago, and some new ruggedized (and expensive) laptops have serial ports, but all laptops have USB.

USB-to-serial adapters are plentiful though many have serious problems with cheap components making them not usable with most software (i.e. Prolific). To date the brands I found reliable are Belkin and IOGear. Many people praise Tripp Lite Keyspan High-Speed USB to Serial Adapter (USA-19HS), http://www.tripplite.com/en/products/model.cfm?txtSeriesID=849&txtModelID=3914. Don’t bother saving a few bucks by spending time to find one for $20 instead of $30, just get a good adapter and be done with problems

Following are step-by-step instructions to put your USB-to-serial adapter to a known Com port number. Let’s say you installed Icom programming software (RSS), connected the RIB cable (almost all have 9-contact RS232 D-connector) from radio to your USB-to-serial adapter. You set the Com port in the RSS program but now need to match the com port of the USB-to-serial adapter. Following is for MS Windows XP, these steps can be used for newer and older versions of Windows, specifics may be a little different.

1. Open Control Panel, go to “Start” and select “Control Panel”

2. Double click “System” in the Control Panel.

3. In System Properties, click “Hardware” tab.

4. Then click “Device Manager” button.

5. “Device Manager” shows PC hardware, click the “+” for “Ports (COM & LPT) ”

6. Right click “(COM1) Properties” (your COM may have different title), this window will appear,

7. Click the “Port Settings” tab, this will show bps, data bits, parity, etc for that COM port.

8. Click “Advanced...” button, below will have COM Port Number.

9. Pull down or scroll to which “COM Port Number” to set appropriate COM # (some may be in use).

10. When done, click the “OK” or “Apply” button on each window which will close it.

Other stuff:

Steps in brief:

  1. Open Control Panel, go to “Start” and select “Control Panel”
  2. Double click “System” in the Control Panel.
  3. In System Properties, click “Hardware” tab.
  4. Then click “Device Manager” button.
  5. “Device Manager” shows PC hardware, click the “+” for “Ports (COM & LPT) ”
  6. Right click “(COM1) Properties” (your COM may have different title)
  7. Click the “Port Settings” tab, this shows baud rates and bits for that COM port.
  8. Click “Advanced...” button, below will have COM Port Number.
  9. Pull down or scroll to which “COM Port Number” to set appropriate COM # (some may be in use). 10. When done, click the “OK” or “Apply” button on each window which will close it.


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