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Reset COM and LPT ports on Windows 10

cedreatlas Posted messages 2 Status Member -  
flo88 Posted messages 28492 Registration date   Status Contributor Last intervention   -

Hello, I am on Windows 10 and I only have one COM/LPT port left, it’s probably due to removing USB devices without caution. I knew a trick to restore all the ports but I can't remember it. I work with Arduino and it's impossible to have 2 different ports, so it's complicated; do you have that trick?


3 answers

  1.
    jeannets Posted messages 28402 Registration date   Status Contributor Last intervention   Ambassadeur 6 603
     

    Hello,

    In segment 40:00-01 is the address of Com1: F803 hex therefore =03F8

    In segment 40:00-03 is the address of Com2: F802 hex therefore =02F8

    Com3: and Com4: are not assigned, but you could do it at your choice.

    That's it for the addressing... You just need to get a DB9 connector from the motherboard...

    Generally, these connections exist on the motherboard, see the manufacturer’s manual, or the silkscreen on the printed circuit board... You just have to connect with a ribbon that comes out in DB9 at the back...

    You can also do this for 'LPTx' parallel printer outputs...

    Then, you need to provide this port number in your Arduino software...

    You will no longer have these issues and a port for each...

    To do this, you need to boot in DOS (from a USB) and use the "Debug" utility
    here are the Debug commands https://www.gladir.com/OS/MSDOS/debug.htm

    That's the principle... you just need to do some testing and experiment a bit..!!

    It may seem outdated... but it's not that complicated and it works.

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  2. cedreatlas Posted messages 2 Status Member
     

    Hello, thank you but I programmed with Arduino a few years ago and I had several COM ports, I don't understand why they have disappeared...

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  3. flo88 Posted messages 28492 Registration date   Status Contributor Last intervention   Ambassadeur 5 170
     

    Hello

    I'm on Windows 10 and I only have one COM/LPT port left

    LPT is a parallel port, the COM port is something else. I don't understand this unnatural mix.

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