Actions
Forum Thread Details
  • Replies 1 reply
  • Subscribers 386 subscribers
  • Views 94 views
  • Users 0 members are here
Related

A quick way to map physical RS232 connectors to Windows COM ports

ehsanshenavar

Disclosure: I developed the PORTYX application mentioned below.

When working with a multi-port USB-to-RS232 adapter, Windows shows several COM numbers but does not make it obvious which physical DB9 connector corresponds to each one. On an 8-port StarTech ICUSB2328I, checking ports one by one in Device Manager was cumbersome.

The method I use is:

1. Attach a DB9 RS232 loopback tester to one physical connector.
2. Run a loopback scan across the available COM ports.
3. Record the COM port that successfully echoes the transmitted data.
4. Move the tester to the next connector and repeat.

I added this workflow to PORTYX RS232 Loopback Assistant so the scan and identification are automatic.

Microsoft Store:
apps.microsoft.com/.../9nfdlhgtpsnx

The method is not specific to that StarTech model and should work with other multi-port USB-to-RS232 adapters. A suitable hardware plug can be found by searching for RS232 DB9 loopback tester.

I would be interested in results from other adapter chipsets or port counts.

  • Interesting idea, but it is quite a expensive toy considering that at the end it is pretty simple loop. Also note that It could be also dangerous since it likely transmit data to 3rd party "generic" devices to "test them". Finally, Windows also has new API since Windows 10 which no longer use COMx devices which are inheritance from DOS era. Especially in case of newer Windows-on-ARM boards, your tool will not identify onboard ports simply because new drivers (SerCx2 based) no longer creates these legacy devices and new API (or huge amount of Win32 work) is required for accessing them.