Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I need to support a trackball mouse (Make:- Cortron Inc) with a 9Pin serial port connector in my application (qt VS2008). This mouse is not getting recognized by my OS (Windows XP) (I dont see the cursor). I do not have a driver and I have not been able to find the device specification online. I tried to get the mouse inputs by writing the COM1 listener as decribed in link The code doesnt give any error but I donot see any values in the bytes I read. I have changes the baud rate and timeout parameters. The interesting part is that I have seen this mouse work inside another application (here too I dont see the cursor when this app is not running) in a different PC same OS.

I have attached another trackball mouse (Make:-A 4 Tech) with same 9pin serial port and this one works (shows me the mouse cursor, behaves like regular system mouse). Even here I have not installed any driver nor do I get the error message. The COM1 listener says "Invalid handle" and portmon.exe (Com port sniffer) tells "Portmon could not attach to Serial0 - the device may be in use". What could be the problem? Is a driver mandatory? I need to support the Cortron Inc trackball not the A4 Tech one.

share|improve this question

migrated from Sep 8 '11 at 20:18

This question came from our site for professional and enthusiast programmers.

I can detect the trackball now :). The issue was with the serial port settings which werent mentioned in the site. This mouse follows Mouse system Rs232 protocol. Once the correct parameters were passed the inputs started getting captured. For more protocol details you can look up to

share|improve this answer
Glad to see you figured it out. – music2myear Sep 12 '11 at 14:28
@kashish Don't forget to associate your SO and SU accounts! This way you'll be able to take control over the question and then accept your answer, which is the proper procedure in cases such as this one. – AndrejaKo Sep 12 '11 at 15:53

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.