port assignments windows

How to Check Ports in Use in Windows 10 & 11

Can’t use a specific port? Here’s how to check which port is in use in Windows with simple commands and apps like currports and tcpview.

Windows has many applications connected or trying to connect to the internet at any point in time. With all those applications, it is only natural that they use many network ports.

Two or more applications may need the same port to work from time to time. When that specific port is already in use by one application, the other application cannot use that port, and it may show a warning message, error out, or crash entirely.

In those situations, it is better to know which ports are used and which application is using that specific port. That way, you can either change the port or terminate the problem-causing application so that the other one works as it should.

The good thing is that it is pretty easy to know which port is used by which application in Windows . So, without further ado, let me show the steps to find which ports are used in Windows 10 and 11 operating systems.

Note: The methods shown below work in Windows 7, 8, 10, and 11.

Table of contents:

Command to check ports in use

• Using CurrPorts
• Using TCPView

Using a single command, you can get a list of all the ports in use by various programs. This method is quite helpful if you want to take a quick glance at the ports in use.

1. Search for “cmd” in the start menu, right-click on the Command Prompt and select “Run as Administrator.” This option lets you open the command prompt with admin rights.

2. In the elevated command prompt window, execute the below command. You can copy and paste the command into the Command Prompt window by right-clicking inside it.

3. You will see the port number right next to the IP address (ex: 192.168.42.198: 50943 ) in the output result. You can see the highlighted portion of the attached image for better representation.

Keep in mind that the list will not be refreshed automatically. You have to execute the command again when you need an updated list. If you want the used port list to be updated automatically, follow one of the two methods illustrated below.

Use CurrPorts to find ports in use

Nirsoft Utilities has a pretty neat and lightweight tool called CurrPorts. It shows all the ports used by Windows and other programs. Let me show you how to use the application to get the information you need.

A quick note: In case you don’t know, Nirsoft has a lot of small and portable apps that are pretty useful in day-to-day life. If you’ve never used Nirsoft Utilities, browse the developer site and find many interesting little tools.

1. First, download CurrPorts from the official website. Being a portable application, you don’t have to install it. After downloading, extract the exe file from the zip file and double-click the file to open it.

2. As soon as you open the window, the application will list all the connections and their ports. You can find the port number under the Local Port section.

3. Being a dedicated port monitoring application, it offers quite a few options to manage the applications and ports. Right-click on any option, and you will see appropriate options like the ability to close the TCP connection, copying properties, application properties, etc.

4. If you want finer control, you can create your own filters to narrow down the search. To do that, select “Options -> Advanced Filters” option.

Use Sysinternals TCPView to check ports in use

Sysinternals TCPView is a Microsoft tool that makes it easy to view all the TCP connections and ports used in Windows 10 and 11. The tool is very similar to CurrPorts.

1. Download TCPView from the Sysinternals website, extract the exe file to your desktop, and double-click on it.

2. As soon as you open the application, you will see a user agreement. Agree to the agreement, and you will instantly see all the TCP connections and ports in use. You will find the port numbers under the Local Port section.

3. You can end the connection and free the port if you want to. To do that, right-click on the connection and select “End Process.” This will terminates the process.

That is all. It is that simple to find which ports are used in Windows 10 and Windows 11. If you like this article, check out how to change the network name in Windows 10 and how to show download and upload speed on the taskbar in Windows .

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How-To Geek

How to check open tcp/ip ports in windows.

Everything that connects to the Internet uses ports in one way or another,

Hannah Stryker / How-To Geek

Read update, quick links, how do ports work, use built-in tools to see what is listening on a port, use nirsoft currports to view what is listening on a port, key takeaways.

• Run the command "netstat -ab" in an elevated Command Prompt, PowerShell, or Terminal window to see a list of applications and their associated ports. This works in Windows 11 too.
• Checking open ports can be done using built-in tools like Command Prompt or PowerShell, which list active ports and the associated process names or identifiers.
• The freeware application CurrPorts by NirSoft provides an easier way to view what is listening on a port, displaying detailed information about the process and allowing for better management of ports.

Whenever an application wants to make itself accessible over the network, it claims a TCP/IP port, which means that port can't be used by anything else. So how do you check open ports to see what application is already using it?

We've tested this process and confirmed that all of the steps are up-to-date, and that they all work in Windows 11, too.

An IP address specifies a computer — or other network device — on a network. When one device sends traffic to another, the IP address is used to route that traffic to the appropriate place. Once the traffic reaches the right place, the device needs to know which app or service to send the traffic on to. That's where ports come in.

If the IP address is akin to a street address on a piece of mail, the port is something like the name of the person at that residence who gets the mail. For the most part, you don't need to worry about ports. But once in a while, you might encounter an app that's set to listen for traffic on the same port that another app already has in use. In that case, you'll need to identify the app that already has that port in use.

There are a number of ways to tell what application has a port locked, but we're going to walk you through a couple of built-in ways that use the Command Prompt , PowerShell , or the Terminal , and then show you a great freeware application that makes it even easier. All these methods should work no matter which version of Windows you use.

We've got two commands to show you. The first lists active ports along with the name of the process that's using them. Most of the time, that command will work fine. Sometimes, though, the process name won't help you identify what app or service actually has a port tied up. For those times, you'll need to list active ports along with their process identifier numbers and then look those processes up in Task Manager.

Option One: View Port Use Along with Process Names

First, you'll need to open the Command Prompt in administrator mode. Hit Start, and then type "command" into the search box. When you see "Command Prompt" appear in the results, right-click it and choose "Run as administrator," or click "Run as Administrator" on the right.

You can also use PowerShell or Terminal for this.

At the Command Prompt, type the following text and then hit Enter:

netstat -ab

After you hit Enter, the results may take a minute or two to fully display, so be patient. Scroll through the list to find the port (which is listed after the colon to the right of the local IP address), and you'll see the process name listed under that line. If you'd like to make things a little easier, remember that you can also pipe the results of the command to a text file . You could then just search the text file for the port number you're after.

Here, for example, you can see that port 49902 is tied up by a process named picpick.exe. PicPick is an image editor on our system, so we can assume the port is actually tied up by the process that regularly checks for updates to the app.

Option Two: View Port Use Along with Process Identifiers

If the name of the process for the port number you're looking up makes it difficult to tell what the related app is, you can try a version of the command that shows process identifiers (PIDs) rather than names. Type the following text at the Command Prompt, and then hit Enter:

netstat -aon

The column at the far right lists PIDs, so just find the one that's bound to the port that you're trying to troubleshoot.

Next, open up Task Manager by right-clicking any open space on your taskbar and choosing " Task Manager ." You can also hit Ctrl+Shift+Esc.

If you're using Windows 8, 10, or 11 switch to the "Details" tab in Task Manager.

In older versions of Windows, you'll see this information on the "Processes" tab. Sort the list of process by the "PID" column and find the PID associated with the port you're investigating. You might be able to tell more about what app or service has the port tied up by looking at the "Description" column.

If not, right-click the process and choose "Open file location." The location of the file will likely give you clues as to what app is involved.

When Once you're there, you can use the End Process, Open File Location, or Go to Service(s) options to control the process or stop it.

If you aren't really the Command Prompt type — or you'd rather just use a simple utility to do all this in one step — we recommend the excellent freeware CurrPorts utility by NirSoft. Go ahead and download the tool. Just make sure you get the right version (the regular version is for 32-bit Windows and the x64 version is for 64-bit Windows). It's a portable app , so you won't need to install it. Just unzip the download folder and run executable.

In the CurrPorts window, sort by the "Local Port" column, find the port you're investigating, and you can see everything — the process name, PID, port, the full path to the process, and so on.

To make it even easier, double-click on any process to see every single detail in one window.

When you've determined what app or service has the port you're investigating tied up, it's up to you how to handle it. If it's an app, you may have the option to specify a different port number. If it's a service — or you don't have the option to specify a different port number — you'll likely have to stop the service or remove the app.

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How to Check for Ports in Use in Windows 10

At any one time, there’s a whole bunch of information being sent between your Windows 10 PC and the endless void of the Internet. This is done using a process whereby network-dependent processes seek out TCP and UDP ports, which they use to communicate with the Internet. First, your data gets sent to remote ports at the destination or website your processes are trying to connect to, then it gets received at local ports back on your PC.

Most of the time, Windows 10 knows how to manage ports and ensure that traffic is being directed through the right ports so that those processes can connect with what they need to. But sometimes two processes may be assigned to one port, or maybe you just want to get a better picture of your network traffic and what’s going in and out.

That’s why wrote this guide that shows you how to check open ports on Windows and see which applications are using which ports.

Also read: How to Set Up Port Forwarding in Windows

Check Port Usage With Nirsoft CurrPorts

NirSoft is one of the best indie software developers, giving us great utilities, like PassView and WirelessKeyView. While some people will prefer checking their ports without installing third-party software (in which case, scroll down to the CMD method), CurrPorts is easily the fastest and most convenient way to check port status on Windows.

Once you’ve installed CurrPorts, just open it to see a list of all your ports currently in use. If you’re looking for local ports in use, just click the “Local Port” column at the top to order the list by port number (handy if you’re looking for a specific one). You can do the same thing with remote ports, too.

If you want to really find specific ports, click the “Advanced Filters” icon at the top and enter your string in the format they suggest. It should look something like the below image.

Hit OK when you’re ready, and the list will filter down to your queries.

Also read: How to Open Ports and Set Up Port Forwarding on Your Router

List Open Ports Using the Command Prompt

The integrated – though not necessarily the simplest – way to check open ports is to use the trusty command prompt.

Click the Start button, type cmd , then right-click “Command Prompt” when it shows up in the search results. Click “Run as administrator.”

Once you’re in the elevated command prompt, enter the following command:

This will steadily bring up a list of open ports that is probably quite long, along with the Windows processes that are using them. (You can press Ctrl + A , then Ctrl + C to copy all information to the clipboard.) On the average PC, there will be two main local IP addresses that contain ports on your PC.

The first, in our case, is “127.0.0.1.” This IP address is otherwise known as “localhost” or a “loopback address,” and any process listening to ports here is communicating internally on your local network without using any network interface. The actual port is the number you see after the colon. (See image below.)

The bulk of your processes will probably be listening to ports prefixed with “192.168.xxx.xxx,” which is your IP address. This means the processes you see listed here are listening for communications from remote Internet locations (such as websites). Again, the port number is the number after the colon.

Also read: How to Disable USB Ports in Windows 10

Install TCPView to Check Open Ports

If you don’t mind installing a third-party app and want to have more control over what’s going on with all your ports, you can use a lightweight app called TCPView . This immediately brings up a list of processes and their associated ports.

What make this better than the command prompt is that you can actively see the ports opening, closing and sending packets. Just look for the green, red and yellow highlights. You can also reorder the list by clicking the column headings, making it easier to find the process you want or two separate processes vying for the same port.

If you do find a process or connection you want to close, just right-click that process. You can then select “End process,” which is exactly the same function as the one in Windows task manager. Or you can click “Close Connection” to leave the process open but stop it from listening on a given port.

If you’re having some trouble in Windows 10, then see whether a Windows update may be causing it . We also have a handy guide for managing the health of your hard drive in Windows 10 .

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Tech writer at Make Tech Easier. Enjoys Android, Windows, and tinkering with retro console emulation to breaking point.

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How to Check If a Port Is Open in Windows 10

You can use a Windows command or third-party utilities

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What to Know

• Easiest: Open the Start menu > type command > right-click the Command Prompt app > Run as administrator .
• Type  netstat -ab  > press  Enter > look for items in the "LISTENING" state. 
• The alternative is to use a third-party app: We like TCPView, Nirsoft CurrPorts, and PortQry Command Line Port Scanner.

This article outlines how to check for open ports in Windows 10, which is necessary if an application cannot access the internet or you want to block an application.

How to Check If a Port Is Open With Netstat

The easiest way to check if a port is open on Windows 10 is by using the Netstat command . 'Netstat' is short for network statistics. It will show you what ports each internet protocol (like TCP, FTP, etc.) is currently using.

The command has many parameters, but the ones you'll need to use to check if a port is open are (a), which provides the active ports, and (b), which will tell you the name of the processes using those ports.

Select the Start menu and type "command." Right-click on the Command Prompt app and select Run as administrator .

Type netstat -ab and press Enter . You'll see a long list of results, depending on what's currently connecting to the network. You'll see a list of running processes. The open port numbers will be after the last colon on the local IP address (the one on the left).

Look for the items on the list with a state of "LISTENING." These are the processes that are communicating via one of the currently opened ports.

If you want to know the program's name that has a specific port open, then type netstat -aon and press Enter . This command will show the protocol the app is using, the local and remote IP addresses, and most importantly, the PID of the application using that port (the number on the far right). Remember to look for the LISTENING status.

To find the application related to that PID, right-click the task manager and select Task Manager . Select the Details tab. Look in the PID field for the PID you noted from the command prompt screen.

How to Check If a Port Is Working Using Third-Party Apps

If you don't want to use the command prompt to check for open ports, there are very easy-to-use third-party apps that can help.

TCPView is a utility included in Microsoft Sysinternals that shows you a list of all running processes and their associated open ports. This app displays ports opening and closing and packet transfers, all in real-time.

Nirsoft CurrPorts

Nirsoft CurrPorts  is another utility to see all ports currently being used by applications and services on your system. Just look for the  local ports  column to see which of your computer's ports are active.

The list also includes ports that are being connected to on the remote end (the server out on the internet).

PortQry Command Line Port Scanner 

Install PortQry Command Line Port Scanner for another command-line utility dedicated to scanning your computer for open ports. Once you install it, open Command Prompt in administrator mode . PortQry automatically installs in the C:\PortQryV2 directory, so change the directory of your command prompt to that directory.

Type the command portqry.exe -local to see all open TCP and UDP ports for your machine. It'll show you everything you can see with the NetStat command, plus port mappings and how many ports are in each state.

What Is a Port?

Applications running on your computer reach out and get information and data from servers elsewhere on the internet. These applications and the server know how to communicate based on their IP address and the port number.

Think of the IP address as a street address and the port number as the apartment number. If either the server or application attempts to communicate using any other port number, it won't work. Every other door will be "locked" because other ports are closed.

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Change COM Port Number programmatically

In Device Manager, I can right click on a serial device, navigate to the Port Settings tab, click Advanced, and change the COM Port Number via a drop-down menu.

I need to automate this step across a large number of PCs. Is there a way to script this process, or to do it programmatically?

• serial-port

• Are they all the same version of Windows? –  End Anti-Semitic Hate Dec 11, 2014 at 6:46
• They are not - could be WinXP, Win7, or Win8. Having said that, I'll happily accept a solution that only works on one (better than nothing!) –  Matthew King Dec 11, 2014 at 6:51
• Hmmm....curious what is the specific application for this process? –  mdpc Dec 11, 2014 at 7:22

This question is probably best asked on stack overflow . That said, take a look at ComDBReleasePort and ComDBClaimPort in the COM Port Database . However, changing COM port assignments programmaticly is not exactly considered a best practice. For example, what happens if two more more concurrent applications are fighting to get the same COM assignment?

Windows dynamically assigns COM port numbers for a good reason. Ideally, your application should be written so that it searches for the specific COM port it needs. This can be done via polling or by using the Windows Management Interface (WMI) .

If you're referencing some application that someone else wrote, and you're just stuck with someone else's program design (or lack thereof), then you may want to consider adding a batch script to modify the registry key under HKLM\Hardware\DEVICEMAP\SERIALCOMM at startup, since the new value(s) are not likely to hold between re-boots.

I don't know how how well this last option would work, but if you're a serious PowerShell or Python user, you could theoretically use either scripting language to directly access the APIs mentioned at the beginning of my response for a one-time COM port re-assignment.

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Not the answer you're looking for browse other questions tagged windows serial-port com-port ..

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How to View Computer Port Assignments

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With 65,535 possible ports to keep track of, you might think viewing the active ports on your small business' computer is a difficult task. In most cases, the number of assigned ports on the computer will be much smaller than the maximum number. In fact, most computers will use only a few port assignments during normal operation. There is a simple method to view your currently assigned ports in a DOS session with a single command.

Press the “Windows-R” keys.

Type “cmd” without the quotation marks in the “Run” dialog box and click the “OK” button.

Type “netstat -n” at the command prompt and press the “Enter” key. A list of active connections and their port assignments will be displayed on the screen. The assigned port numbers appear immediately after the colon at the end of your IP address.

• The TCP/IP Guide: TCP Common Applications and Server Port Assignments
• Internet Assigned Numbers Authority: Service Name and Transport Protocol Port Number Registry
• A complete list of options for the netstat command is available by typing “netstat/?” at the command prompt.

Finn McCuhil is a freelance writer based in Northern Michigan. He worked as a reporter and columnist in South Florida before becoming fascinated with computers. After studying programming at University of South Florida, he spent more than 20 years heading up IT departments at three tier-one automotive suppliers. He now builds wooden boats in the north woods.

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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. 10,515 questions Sign in to 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.

-------------------------------------------------------------------------------------

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

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

  Windows OS Hub / Windows 10 / How to Clean Up or Reset COM Port Numbers in Windows

How to Clean Up or Reset COM Port Numbers in Windows

A number of legacy applications are able to address only two-digit COM port numbers, and won’t work with COM100 and higher. In the worst cases, these programs work only with COM1-COM9 ports. What if a device has got a higher COM port number?  Is it possible to reset the numbering for reserved COM ports and delete assigned ports?

How to Change a COM Port Number for a Device in Windows?

Find out which process is using a serial com port in windows, resetting com port numbers in windows registry.

In Windows, you can manually change the COM port number assigned to a device. Suppose the necessary COM port is already busy, and you want to try to free it.

• Open the Device Manager by running the devmgmt.msc command;

• Then expand Ports (COM & LPT) and find your device in the list;
• Go to the Port Settings tab and click the Advanced button;
• The current COM port number assigned to the device can be found in the COM Port Number field;

But more often you cannot change the assigned COM port number to another one in the hardware properties, since all the “lower” COM ports are already in use.In this case, you need to try to remove the COM port reservation

• Expand the Ports (COM & LPT) branch, find which COM port number you need is assigned to (a pale icon means that this COM port is assigned, but this device is not currently connected);

Get-WMIObject Win32_SerialPort | Select-Object Name,DeviceID,Description You can get the COM port number for a specific device by its name, for example:

Get-WMIObject Win32_SerialPort | Where-Object { $_.Name -like "*Arduino*"}|select name, deviceid or Get-WMIObject Win32_SerialPort | Where-Object { $_.Name -like "*GPS*"}|select name, deviceid

You won’t be able to release the COM port of a device that is used by Windows or a running program (process). First, you need to stop the process that is currently using the COM port. You can use the Process Explorer tool (by Sysinternals) to find out the name of the process using a particular COM port number ( https://docs.microsoft.com/en-gb/sysinternals/downloads/process-explorer ).

First, you need to display the name of the service that uses the COM port. Run the PowerShell command:

get-pnpdevice -class Ports -ea 0| Select Name, PNPDeviceID, Status, Service

The service name of the specific COM port is shown in the Service column. For example, for COM2 it is Serial . Now you need to run Process Explorer as an administrator and select Find -> Find Handle or DLL from the menu. In the Handle or DLL substring line, enter the Service value obtained earlier. In our example, this is Serial .

Process Explorer should show the process name that is currently using your COM port. To release the COM port, kill the process or program.

Information about the COM ports in use is stored in CommDB registry parameter under the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\COM Name Arbiter reg key.

• Unplug all external devices and restart your computer;
• After the reboot, connect the devices in the necessary order, reinstall USB-to-serial converters, etc. All detected COM port devices will be automatically detected by the system and assigned sequential COM port numbers.

You can also use the following free tools to clean up reserved COM ports:

• Device Cleanup Tool – the utility is used to search the registry for previously connected devices (under the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum ), remove unused devices, and clear COM port reservations.

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Hi dear When I open Device Manager there is no branch of (COM & LPT) to expand. How can I Add or Find it?

thank you so much

thanks you so much , life saving post 🙂 , i mostly work with iot devices and sometime com ports get busy and am getting com port busy returns in code so this saved my life in flushing com port

Thank you for the post, very helpful

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How to change asynchronous serial COM port assignments in Windows Device Manager

Sealevel recommends using the installed COM numbers if at all possible to avoid system conflicts. If you previously installed a USB or PCMCIA serial interface, it will have resources assigned by the operating system. If the device is not currently connected to your computer, these COM assignments will not be apparent and forcing new COM port assignments will create a conflict when the devices are reconnected at a later time.

One scenario where you would have to change the COM port assignments is when your legacy application only works at COM1 through COM4 and the Sealevel serial device you installed comes in at COM5 or higher. Another scenario might occur when you install a multiport serial card and the COM port numbers are not assigned consecutively and you want them to appear consecutive.

In Windows 7, Vista, XP or 2000 operating systems, you can change the COM number assignment using Windows Device Manager.  To change the COM port assignments in Device Manager, follow these basic steps:

1) Click the Start button.

2) Right-click on My Computer.

3) In the fly-out menu, click Manage.

4) In the Computer Management Window, click on Device Manager.

5) In the right-hand pane, expand the Ports (COM & LPT) listing by clicking the “+” symbol.

6) Right-click on the COM number you want to change and select Properties from the fly-out menu.

7) In the Communications Port Properties window, click the Port Settings tab and then click the Advanced button.

8) In the Advanced Settings window, you can select the new COM port number from the drop box (be careful not to select a COM number already in use).

9) Click the OK button to confirm your changes. If Windows detects a conflict, choose another COM port number.

10) Click the OK button to close the Communications Port Properties window.

11) When Device Manager refreshes the hardware list, the COM assignment will reflect your changes. To get Device Manager to refresh the window on Windows XP, you may need to click ‘Action’ in the menu and then click ‘Scan for hardware changes’ in the sub-menu (Note: If ‘Scan for hardware changes’ isn’t listed in the sub-menu, click on the computer name in the right pane and then repeat this step).

Contact our technical support department if you are still experiencing problems with serial COM port assignments.

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How to identify Com Ports in Windows10

The new device manager in windows 10 is not showing the "com port" numbers.  Such as COM1 COM2 and so on.  If I open the serial bus controller line in device manager it does not provide the port information.

What I am trying do is connect to my network switch with a terminal emulation program via an Ethernet cable out of the back of the switch.  I know it works since I used it on an old win7 computer. But that computer is long gone.    9600, 8, none, 1.  COM1, COM2, or whichever port I happened to be plugged into.  But I can't verify what COM PORT I am using.   

If someone can point me in a direction, it would be a big help.  I have done all the net searches I can think of.

Thanks in advance.

***Modified Title from: Identify Com Ports in windows10***

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Replies (5) .

• Microsoft Agent |

Thank you for writing to Microsoft Community Forums.

We understand your concern. However, serial bus controller in Device Manager contains USB devices and USB port numbers and it seems COM Ports devices might be hidden, so please follow the steps mentioned below and check if you can see the Com Ports.

Open Device Manager .

Click on View in the menu bar and select Show hidden devices .

Locate Ports (COM & LPT) in the list.

Check for the com ports by expanding the same.

Hope it helps.

210 people found this reply helpful

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Thanks for your feedback.

below is version number of the device manager I have on my machine.

Version: 10.0.17134

There is no com or lpt port line on this version.  It did show as described on my win7 machine but not on this version of device manager.  I had "shown hidden devices" before, but to no avail, and I just double checked it again after reading your response.  And thank you for the response.  But so far I can still find nothing that associates usb devices to com ports on this machine.  I had expanded the serial bus controller tree and checked properties of the three usb devices (generic usb hub, usb host controller and usb root hub) connected   Still no com port information.  

If you can give me another idea it will be a big help.  After a couple of days of chasing information down on the net, and so far with no luck, it has been frustrating.  You wouldn't think Microsoft would make information that is needed so often so hard to dig out.  BTW I also went thru properties on all the items under HID as well.  Still nothing that showed com ports.

Thanks again.  Have a great day.

Thomas 

47 people found this reply helpful

Thank you for your response.

We apologize for the delayed response. In this case, please refer to How to include a screenshot in your post and provide us screen shot of Device Manager Window after enabling Show hidden devices , so that we can assist you further.    

11 people found this reply helpful

Thanks for the reply.  Device manager screenshot is attached.  Have tried all suggestion and so far no luck.  The below was copied just after "show hidden devices".  Still no "COM and LPT PORTS"

65 people found this reply helpful

We truly apologize for the delayed response. In this case, please let us know the make and model of the computer, so that we can guide you further.

  Also, kindly follow the steps mentioned below and check.

Click on Action in the menu bar and select Add legacy hardware > Next .

Select Install the hardware that I manually select from a list (Advanced) and click Next .

Scroll down, then select Ports (COM & LPT) and click Next .

Select the Manufacturer accordingly and click Finish .

262 people found this reply helpful

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FvHemert (Customer) asked a question.

I have CP210x USB to UART Bridges installed on a Win10 computer. One is assigned COM3, the other one COM8. After a reboot the com ports are swapped and the connected devices no longer work.

Is there any way to fix the com port assignment?

I found several articles on this topic, also on the forum. They have dead links or do not apply to WIN 10.

M880586414 (Employee)

 According to 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. 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. 

C836205753 (Employee)

Hi @FvHemert,

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:

1. Open Windows Device Manager > right click the device > Properties

2. Under Port tab > Advanced

3. Change COM port number

FvHemert (Customer)

Hi Stephen,

Thank you for your answer, I understand how to change the com port for a device.

This however is not my problem.

Just like in you screen shot I have 2 devices configured:

 - Serial device A on com8

 - Serial device B on com3:

The problem is that as soon as I reboot my machine Device A will be on com3 and Device B on com 8 and nothing works anymore because device A and B are totally different and controlled by different programs.

My question: how do I configure a static assignment so Device A will always stay on com 8 and Device B on com3? Regardless reboot or power down?  I am using Windows 10.

Hi @FvHemert

As I mentioned, Windows manages the COM port number assignments, and a device's COM port number may change after a reboot. I am not aware of any way to make an assignment static through a reboot.

cgiga (Employee)

Can you try using the AN721 software to view the contents of the CP210x devices?  In particular take a look at the serial number of the devices?  If they are the same, can you try changing the serial number of one of the devices and see if the com port assignments stay as originally defined after plugging them back in?

http://www.silabs.com/products/Interface/Pages/interface-application-notes.aspx

JH (Employee)

Which device are you using, CP2102/3/4/5/8? Do your two devices have same serial number?

If not reboot your machine, just remove the device and then plug it into USB port again, is the COM port number same as before?

Thanks for getting back to me. I am currently on a business trip and do not have access to the devices.

Will test and report back as soon as I am back home again.

H515662839 (Customer)

Can you clarify if your question refers to having your COM ports also re-enumerated after a reboot?

If yes, what Windows 10 update you're referring to that may be the problem?

And what Windows 10 version was working for you, at least in the sense you did not notice the COM ports re-assigned, but that remained relatively static?

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