COM3 COM4 ports missing

  1. Posts : 4
    Windows 10

    COM3 COM4 ports missing

    I have posted this thread in General support but now I think this section may be better.

    WINDOWS 10
    I am working it with Arduino microcontrollers connecting them via ports com3 or com4.
    I had a random problem where half of the time communication did not work. I was receiving semaphore time out problems.
    The problem was usually going away after the series of restarts. I was trying to find a permament fix. I thought there is something wrong with COM3 and COM4 settings. I tried to delet and install them anew and now I don't see them anymore. And have no clue how to fix it.
    In Control Panel automatic scan for new hardware is not detecting them.
    I am including two screenshots to describe my dilema.
    I managed to somehow enable the communication to work on COM4 last night.
    Now as you can see I see no COM3 COM4 in Control Panel but when I list the list of ports it shows COM4 as Busy.

    Any help would be greatly appreciated
    Attached Thumbnails Attached Thumbnails COM3 COM4 ports missing-com.png   COM3 COM4 ports missing-com_1.png  
      My Computer

  2. Posts : 57
    Windows 10 pro en

    Com3 and Com 4 are on a separate PCI(E) card - right?
    If so, remove the card, clean the contacts and plug it back in.

      My Computer

  3. Posts : 6,963
    windows 10

    They normally share with com1 and 2
      My Computer

  4. Posts : 57
    Windows 10 pro en

    Samuria said:
    They normally share with com1 and 2
    I don't understand what you will say.

    During Windows installation of my PC with two serial ports onboard, they were numbered with Com1 and Com2.
    Later I installed one additional Pcie Com card. These channels got the numbers 3 and 4.

    My questian to the threed starter is now, what kind of Com ports are those with numbers 3 and 4.

      My Computer


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