Computer Selects Different Com Port Everytime, Why ???

Discussion in 'Computers, Hardware, and Operating Systems' started by K2WH, Jan 28, 2019.

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  1. K2WH

    K2WH Premium Subscriber Volunteer Moderator QRZ Page

    My computer never uses the same com port whenever I turn it on for rig control.

    Is there a way to make sure the same com port is used every time ?
  2. WF7A

    WF7A Subscriber QRZ Page

    Which version of Windows do you have?
  3. KF5FEI

    KF5FEI Ham Member QRZ Page

    Some "budget" (read Chinese) USB to serial adapters will want you to reload the drivers if you plug the cable into a different USB port. They may also change COM port numbers when plugged into different USB port on the same computer. It may also be related to other serial devices that were plugged in and later removed, but did not release the COM port number.
  4. K1SZO

    K1SZO XML Subscriber QRZ Page

    Are you using an FTDI chip based device? If so, I believe they have some utilities that can help with this.

    The one I remember doesn't appear listed anymore, but they have a utility for com port assignment. Though it's unclear if it will run under Windows 10.
  5. K2WH

    K2WH Premium Subscriber Volunteer Moderator QRZ Page

    Whoa, I am using Win7 (tried win10 a few times and dumped it, didn't like it), and the connection is the same USB port all the time to my FTdx3000 USB port, no FTDI based device, just my FTdx3000.

    I do not use the USB port on my Toshiba laptop for anything else, not cable switching, no other devices.

    I run WSJT-x mode FT8 and it will select one of the three, Com 20, 23 or 4.

    On any particular day it will select one of them and if it does not agree with the port that WSJT-x was using previously, I have to select a new com port out of those 3.

    Basically can I not dedicate a port that will always be used when trying to re-connect to my FTdx3000 ?
  6. K3DCW

    K3DCW QRZ Lifetime Member #212 Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    Are you powering the rig down completely at the end of each day; turning off the rig, powering down the power supply, etc? If so, then stop turning off the power supply and I bet your problems will go away.

    The only time I've seen this issue is when the rig and power supply were both shut off. If you leave the power supply on, the USB port in the rig maintains a slight power draw that keeps it powered, keeping it recognized by Windows, and keeping the port number from changing. YMMV, but I helped another ham solve his similar issues this way.
  7. K2WH

    K2WH Premium Subscriber Volunteer Moderator QRZ Page

    Hmm, I'll try that and yes I do shut the power supply off.

    But I also shut the computer down also.
  8. KP4SX

    KP4SX XML Subscriber QRZ Page

    Bill, I've got a few gadgets connected to my Win7 machine and I completely shut down the power to the shack at night and I'm not losing the COM assignments. However, like K1SZO mentioned, I had an FTDI USB to Serial device that popped up different every time.
    I wonder if you're having some collisions at startup and maybe cleaning up the start menu would help? (msconfig)
  9. W9GB

    W9GB Ham Member QRZ Page

    FIRST, Check How Much GARBAGE you have in your Win7 Device Manager.
    To include Hidden Devices in Device Manager display, click View and select Show Hidden Devices.

    PRIOR to Windows 8, to view nonpresent devices, you must set the environment variable
    DEVMGR_SHOW_NONPRESENT_DEVICES to 1 before you open Device Manager,
    then open Device Manager, and on the View menu, click Show hidden devices.

    To permanently set the user environment variable
    use the Advanced tab of the system property sheet.

    After you set this environment variable, run Device Manager and select Show hidden devices.

    1. Click Start>Run
    2. Type cmd.exe in the textbox and click OK
    3. Type set devmgr_show_nonpresent_devices=1 and hit ENTER
    4. Type cd\windows\system32 and hit ENTER
    5. Type start devmgmt.msc and hit ENTER
    6. When the device manager opens, click the View menu
    7. Click Show Hidden Devices
    The “Ghost” Drivers you will see are “Clogging Up” OS operations.

    High Quality USB Bridge Devices (ICs), like FTDI, follow the standards and use serialization.
    In other words, Windows OS can identify as a unique USB device.

    I have no idea what Yaesu used for their USB interface components or
    How they programmed them.
    Last edited: Feb 19, 2019
    KA9JLM likes this.

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