FTDI Community

Please login or register.

Login with username, password and session length.
Advanced Search  

News:



Welcome to the FTDI Community!

Please read our Welcome Note

Technical Support enquires
please contact the team
@ FTDI Support


Author Topic: Different FTDI devices installing with same COM port number  (Read 190 times)

Me123

  • Newbie
  • *
  • Posts: 7
    • View Profile
Different FTDI devices installing with same COM port number
« on: February 08, 2018, 11:06:16 AM »

I've just got a new laptop (Windows 7 64bit) and I'm having an issue whenever I plug in a new FTDI USB to serial device it installs with the same COM port number.  I can have two devices plugged in at the same time with the same port number, which is obviously a problem.  This didn't use to happen on my old 32 bit Win 7 laptop, and it doesn't happen on some other laptops with 64 bit Win 7 I've tested it out on so I presume it is some issue with my laptop, I just can't think what it is.  I've tried uninstalling/reinstalling the drivers but that didn't help, I'm not sure what else to try. Does anyone have any idea?  Thanks.
Logged

FTDI Community

  • Administrator
  • Newbie
  • *****
  • Posts: 42
    • View Profile
Re: Different FTDI devices installing with same COM port number
« Reply #1 on: February 08, 2018, 02:21:21 PM »

Hello,

Thanks for your question.

There are known issues with Windows 7 and USB 3.0 ports, explained in the following document:
http://www.ftdichip.com/Support/Documents/TechnicalNotes/TN_152_USB_3.0_Compatibility_Issues_Explained.pdf

It is possible that this could be causing the devices to show up with the same COM port number, are you using USB 3.0 ports?

Another possibility is if the devices have the same serial number, you can check and change the serial number using our FT_Prog utility:
http://www.ftdichip.com/Support/Utilities.htm#FT_PROG

Best Regards,

FTDI Community
Logged

Me123

  • Newbie
  • *
  • Posts: 7
    • View Profile
Re: Different FTDI devices installing with same COM port number
« Reply #2 on: February 09, 2018, 10:54:59 AM »

Thanks very much for that information.  The devices do not have the same serial number but all the USB ports on my laptop are 3.0 so that probably explains the source of the weird behaviour.
Logged

Me123

  • Newbie
  • *
  • Posts: 7
    • View Profile
Re: Different FTDI devices installing with same COM port number
« Reply #3 on: February 12, 2018, 08:50:40 AM »

Just a quick update. After plugging in a few more devices they suddenly started to be given different COM port numbers.  Not sure why this started working but thank you very much for the help.
Logged

FTDI Community

  • Administrator
  • Newbie
  • *****
  • Posts: 42
    • View Profile
Re: Different FTDI devices installing with same COM port number
« Reply #4 on: February 12, 2018, 10:13:15 AM »

Hello,

Thanks for your feedback, please let us know if you have any more questions.

Best Regards,

FTDI Community
Logged