title: How does windows map the virtual com port to a device
body: <p>I have run a test to verify, that windows (7 and 8) is capable of remembering the configured com port number for each usb port when i insert an usb->serial converter.</p>
  
  <p>My test was simple:</p>
  
  <ol>
  <li>I have 2 similar USB to Serial converters from the same manufacturer and 1 converter from a different manufacturer.</li>
  <li>I insert <strong>converter no 1</strong> into <strong>USB port no 1</strong> and configure it as COM9 in device manager.</li>
  <li>I pull it out and insert the <strong>converter no 1</strong> into <strong>USB port no 2</strong> and configure it as COM10 in device manager.</li>
  <li>When moving <strong>converter no 1</strong> between <strong>USB 1 and 2</strong> i verify that the configured COM port settings are remembered.</li>
  <li>Using <strong>converter no 2</strong> (From same manufacturer) i verify the same result as with converter no 1.</li>
  <li>Using a <strong>different converter</strong> (from a different manufacturer) i verify that it is assigned to a different COM port (in my case COM4).</li>
  </ol>
  
  <p><strong>Conclusion</strong>: It seems like windows is capable of identifying the inserted converter device, and configure the COM port with its previous setting.</p>
  
  <p><strong>Question</strong>: How does windows identify the inserted device?. I would assume by Vendor and/or Product ID, but I am not sure.</p>