static com port assignment

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how to assign static COM port number to a device

I have an issue with one device ( Pax Technology Terminal ) connected to Win 10 ( NCR Point of Sale ). after unplugging the device and connecting it the COM port number changes and every time we have to change the port number back to the correct port number for this device to work.

Is there way I set this device to only get a certain COM port number every time they unplug and connect it back ?? something like setting defaults for each device type

Windows 10 A Microsoft operating system that runs on personal computers and tablets. 11,899 questions Sign in to follow Follow

Dear all USB Users, (unsure that this is the right forum for my question...)

Is there a way to programmatically "Recover Unused and FIX COM Numbers" (NI - National Instrument Forum Question...)

It is hard to live with the Totally Random USB COM port Enumeration that Windows always apply... Is there a way to make this less Random, or even totally controlled and pre-visible?

I found that for each USB device the following apply (or at least should apply) Each device has:

VID = Vendor ID
PID = Product ID
PSN = Product Serial Number So with we have the possibility to make a COM-Port-Number Reservation/Binding Option for this USB device with Unique ID: VID&PID&PSN This would result in the possibility for having the desired Unique Fixed COMxx Port Number Reservation...

See my proposal in the attached TXT document... 269324-windows-usb-com-port-enumeration-problem.txt

The Simple Solution to this Problem could be just like **DHCP MAC-Address to IP-Address binding... Like VID&PID&PSN to COMxx Port Binding forever on this computer...

Thanks... The World and I would appreciate a COMMENT to this... And much better also an action to this problem...!

Thank you for reading ana all the best regards Ronn

I encountered similar issue. When the COM number is assignated and confirmed, Device Manager is closed automatically and the COM number remains unaffected.

Windows manages the COM port number assignments, and a device's COM port number may change after a reboot.

To manually change the COM port number of a device:

Open Windows Device Manager > right click the device > Properties
Under Port tab > Advanced
Change COM port number

Also, according to the experience before, the Windows assign the COM port according VID, PID and serial number. So with the same device plug in, it should always get same COM port assignment. But when two devices with same VID, PID and serial number might be treated as same device. When you plug in them in sequence, Windows can assign different COM port for them. However, after rebooting the Windows with the two USB devices attached, the COM port assignment should be decided by Windows for the two USB devices with same VID, PID and serial number.

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If the Answer is helpful, please click " Accept Answer " and upvote it.

How can ANY two devices have the same serial numbers ??

Your answer

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How to change the COM port for a ...

How to change the COM port for a USB Serial adapter on Windows 7, 8, 8.1, and 10

Originally authored by: Bernie Thompson, July 4, 2011

Start by going to the Device Manager. Once there do the following: Expand the Ports ‘(COM& LPT)’

You should be looking at something like this:

Device Manager Ports COM and LPT section expanded

As you can see Windows has set the port to COM10. However many legacy applications expect the port to be between 1-4. Let’s change that:Right click on the device and click on ‘Properties’.

Device Manager Ports COM and LPT section expanded menu

Click on ‘Port Settings’. Then click on ‘Advanced…’.

Once you’re in ‘Advanced Settings for COM10’ on the bottom you can see the ‘COM Port Number: COM10’. Click on that to change it to the lowest possible number (between 1-4).

Select COM port number from the drop down menu

Then click ‘OK’ on all open Property Windows. Now the device should look like this:

Verify COM Port number in the Device Manager Port COM and LPT section

Knowledge Article

Reassign com port numbers in windows, question how can i reassign a com port number in windows answer to reassign a com port number in windows, perform the following steps: 1) right-click my computer and jul 9, 2021 knowledge, information, nothing here yet.

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How to Enable COM Port in Windows 10: Step-by-Step Guide

Enabling COM Port in Windows 10 might sound technical, but it’s actually pretty straightforward. By following some simple steps, you can make sure your computer recognizes and uses COM ports effectively. Whether you’re setting up a new piece of hardware, troubleshooting a connection, or tweaking settings for an application, enabling COM ports is a critical skill to have.

How to Enable COM Port in Windows 10

In the following steps, we’ll go through the process of enabling a COM port on a Windows 10 machine. This will involve accessing the Device Manager, modifying port settings, and ensuring your system recognizes the port.

Step 1: Open the Device Manager

First, right-click on the Start button and select "Device Manager" from the context menu.

Device Manager is your go-to tool for managing hardware and drivers on your computer. It displays all the connected devices and allows you to configure them.

Step 2: Expand the Ports Section

Once in Device Manager, find the "Ports (COM & LPT)" section and click the small arrow next to it.

This section shows you all the available COM ports. If you don’t see it, it means no COM ports are currently recognized by your system.

Step 3: Right-click on a COM Port

Right-click on any of the listed COM ports and select "Properties" from the dropdown menu.

The Properties window gives you detailed information about the selected port and allows you to adjust its settings.

Step 4: Navigate to Port Settings

In the Properties window, go to the "Port Settings" tab and click on "Advanced".

Here you can change various settings related to the COM port, such as baud rate, data bits, and more.

Step 5: Change the COM Port Number

In the Advanced Settings, you can change the COM Port number if needed. Click "OK" to save the changes.

Changing the port number can help resolve conflicts with other devices and ensure smooth operation.

Step 6: Confirm and Close

After making your changes, click "OK" to close the Properties window and then close Device Manager.

Your changes will be saved, and the COM port should now be enabled and ready for use.

After completing these steps, your COM port will be enabled, and your computer should recognize it without any issues. This means you can now connect external devices that use COM ports and configure them as needed.

Tips for Enabling COM Port in Windows 10

Check for Updates: Make sure your Windows 10 system is up-to-date to avoid compatibility issues with COM ports.
Use the Correct Drivers: Ensure you have the right drivers installed for your hardware that uses COM ports.
Troubleshooting: If the port doesn’t show up, try restarting your computer or checking the hardware connections.
Port Conflicts: If you experience conflicts, try changing the COM port number in the Advanced settings.
Backup Settings: Keep a record of your port settings before making changes, so you can revert if needed.

Frequently Asked Questions

What is a com port.

A COM port, or communication port, is a serial port that allows for communication between the computer and external devices.

Why don’t I see any COM ports in Device Manager?

If no COM ports are visible, it could be due to a lack of relevant drivers or that no COM port hardware is currently connected.

Can I use multiple COM ports at once?

Yes, you can use multiple COM ports simultaneously, but ensure there are no conflicts in port numbers.

How do I know which COM port my device is using?

You can check the COM port assignment in Device Manager under the "Ports (COM & LPT)" section.

What do I do if my COM port isn’t working?

Check the device’s drivers, ensure no port conflicts, and verify that the hardware is properly connected and functioning.

Step-by-Step Summary

Right-click Start button, select "Device Manager".
Expand "Ports (COM & LPT)" section.
Right-click on a COM port, select "Properties".
Go to "Port Settings" tab, click "Advanced".
Change COM Port number, click "OK".
Confirm changes and close Device Manager.

Enabling a COM port in Windows 10 is easier than it seems. By following the steps outlined in this guide, you can quickly get your COM port up and running. This process involves accessing the Device Manager, tweaking settings, and ensuring the port is recognized by your system.

So, why wait? Get started right away and make the most of your hardware! For further reading, you can explore more about device management in Windows 10 or delve into troubleshooting common COM port issues. Now that you know how to enable COM port in Windows 10, you’re well-equipped to handle any related challenges that come your way.

Matt Jacobs has been working as an IT consultant for small businesses since receiving his Master’s degree in 2003. While he still does some consulting work, his primary focus now is on creating technology support content for SupportYourTech.com.

His work can be found on many websites and focuses on topics such as Microsoft Office, Apple devices, Android devices, Photoshop, and more.

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Is there a way to set the com port to stay constant

Since I up graded my laptop to windows 10. Ground control doesn’t remember the com port. Every time I boot the lap top up I have to set the com port to com3.

Last week it lost the com port during a g code program. And that resulted in major problems and waste of material?

I upgraded to 1.2 today and it seems to be worse I had to select the com port 3 times during calibration.

Thank you for your help in advance

do you have two identical ardunio’s plugged into the windows laptop?

Windows assign the COM port according VID, PID and serial number. So with the same device plug in, it should always get same COM port assignment. However, two devices with same VID, PID and serial number might be treated as same device. When you plug in them in sequence, Windows can assign different COM port for them. However, after rebooting the Windows with the two USB devices attached, the COM port assignment should be decided by Windows for the two USB devices with same VID, PID and serial number.

Hmmm I’ve never heard of the COM port not being constant before. Are you saying that the number changes and you have to select a new one each time you connect, or that Ground Control is not staying connected?

I’m not sure that it is the problem in this case but Windows can assign a comport form 1 - 254. Each time the device can be assigned a new number, it depends on how the device identifies it’s self and the windows registry. If one or both are “less” then 100% then things could go wonky. I’ve seen the same device install 253 times using all the comports.

Also if the device is duplicated but never completed set up you now have 2 of the same product fighting with it’s self for the same space.

Most of the time it goes smoothly. When it doesn’t there is a reason. It normally means something is “boogered.” You could remove all for the com devices and start over, if the issue stems from a hardware issue you can loose access to your USB port until the hardware is repaired or replaced so I normally don’t have users do the delete everything and reboot these days. With laptops that only have 1 port if you loose the hub up stream in the laptop it’s likely you may not be able to use external devices to troubleshoot anymore.

I hope this information is helpful.

It’s always com3, when I click on the shortcut icon to start ground control. It starts up, but before the Adriano/MaslowCNC will move I have to go into the Actions Menu and select Ports and choose Com3

Does that make sense?

Right click on whatever you use to start Ground Control and try run as administrator. Go in set The port, connect. Exit Repeat - see if it remembers

when I click on ground ground control it a window pops up and ask if i would like this program to make changes…I click yes…and it just disappears…

Put ground control on your desktop or somewhere else in your user account. Running it from C: will cause issues on windows 10.

My installs run on a large number of machines from c:\maslow\ Insert folder name here. I wrote an installer that puts it in this location. Not one problem so far - Ok this is a problem but running form c:\ should not be an issue unless it is joined to a domain with group policy that makes it a problem or there is another issue with the pc. I’m going for the latter. Vanilla Win 10 will prompt you for Admin access to write to C: you accept and move on.

There may be another simple answer based on something we are not seeing. However this is an instance where I would consider wiping it and reinstalling windows or moving to Linix on a stick.

The problem with this approach and the standalone version of ground control is that if you have a different version of python with a different package load-out installed on the machine, then it will see that one instead of the embedded version that is included in the portable app. Moving the ground control app to userspace is a troubleshooting step that eliminates that possibility.

The reason I removed it from there is users with long names were hitting file limitations from windows internal file structure names.

I don’t think it’s that the user has multiple versions of Python but Multiple versions of Windows. I don’t have too many upgraded computers. I also suspect a corrupted registry because this is an upgrade.

Just a guess based on my experiences.

I appreciate your input as it is an angle I had not looked at.

My mason files are located on C drive. C:\CNC…

I have tried running it from a short cut, from the directory itself, as admin. However it will. It remember com3 under ports

apologies if this has been said before (I haven’t been following this, but it’s been going on way too long)

There is no way to guarantee that windows will use the same port for the same USB device.

port names are dynamically assigned as (USB) devices get plugged in. If you unplug a device while some software still has it open, the OS cannot remove the port name, and so when you plug it in again, it will get a different port.

In addition, if you plug in a different device, it can get the port number that you want the maslow to get.

There are some tricks that you can try to pull to detect serial numbers and other such things to try and get consistant naming, but they are very fragile and break under fairly common conditions.