One pesky problem with Windows 10, as well as the earlier versions of the Microsoft Windows operating system, is that the COM port assignments for devices that use them, often change. In this post, we show how to change COM port number on USB modem back to what it was before. Or, you can do this to changed assigned port number at will to any unused port you desire.

The steps you take to restart your modem and router can vary, but here are the general steps. (Note: If you have a cable modem/Wi-Fi router combo device, you only need to follow the steps for the single device.) Unplug the power cable for the router from the power source. Unplug the power cable for the modem from the power source. Windows 8, Windows 8.1, and Windows 10 include a number of policies to control connection management. These policies are not exposed in the Windows user interface but can be configured by using the WcmSetProperty API or Group Policy. Press the Windows key+X and choose Device Manager. In the Device Manager, if there is a yellow flag next to a device, right click it and Uninstall it. Remove the USB modem from the computer end. And restart your computer. Open the CD and copy the Driver install files to a folder on your computer.

A USB modem for example, may start off being assigned to COM3 when you plug it in right out of the box. But that assignment can (and often does) change to COM4 or some other COM port, any time the modem is unplugged and reconnected, the computer restarts, a new version of a device driver is installed, a different USB port is used, certain Windows updates are installed, and a myriad of other possible port reassignment triggers.

ModemManager is a DBus-activated daemon which controls mobile broadband (2G/3G/4G) devices and connections. Whether built-in devices, USB dongles, bluetooth-paired telephones, or professional RS232/USB devices with external power supplies, ModemManager is able to prepare and configure the modems and setup connections with them. The Modem Manager lets you configure the various connection methods associated with DLS. To access the Modem Manager, go to Menu - Tools - Modem Manager Configuration. In the Modem Manager window, you can add a connection type, remove a connection type and initiate a modem. There are different options associated with each connection type.

'5) Right click on my computer and select 'Manage'. Once it opens click 'Device Manager', then 'Modems'. 6) Under 'Modems' you should see a Samsung device. Right click it and then select 'Properties'. 7) Once the 'Properties' window opens, select the 'Modem' tab and see what port it is on, like 'COM5' for example.' What i did was i went to device manager and located driver of my usb modem in usb controller by inserting and ejecting my usb modem. Then i uninstalled the driver. I reinstalled it manually by giving it the path C: Program Files (x86) iBall Airway 21.0MP-58 Driver Win864 (the path of its earlier driver).

Of course, when the modem COM port changes, any program that relies on the modem listening on the original COM port, no longer functions correctly. The solution is to change the modem COM port back to the one it was originally using, and the procedure below demonstrates how to do this.

How to Change COM Port on USB Modem, Windows 10

1. Plug USB Modem into Working USB Port on Windows 10 Computer

You won’t be able to change its COM port settings if it’s not connected to your machine when you try.

2. Bring up Device Manager Window

You can find Device Manager in Control Panel, or enter the word -Device- into Cortana’s search box. This brings up a link to -Device Manager- (usually the first one) in the results list. Tap that link, and you’ll see a screen similar to the shot in the next picture.

3. Find the Modems Device Group Item to Continue with How to Change COM Port on USB Modem

The purple arrow points at the Modems group in the last picture.

Then, tap / click the downward pointing arrow immediately to the left of that entry. This expands the Modems device group, as shown in the next picture, revealing any modems currently connected to and operating correctly on your computer. In this demo, we only have one USB modem connected, as listed.

4. Double Click the Entry for the Modem to Change

In our demo here, we’re changing the COM port for the Agere Systems USB 2.0 Soft Modem. So, we double click the entry for that modem, and this brought up the Windows 10 device configuration screen for this modem, as shown next.

5. Then, Click / Tap the Advanced Tab

The purple arrow points at the Advanced tab in the last picture. The configuration window then redraws itself to show the advanced configuration options for this particular modem, as shown in the next picture.

6. Tap / click the Advanced Port Settings Button to Continue with How to Change COM Port on USB Modem

The purple arrow in the last picture points at the Advanced Port Settings button. Doing so brings up the -Advanced Settings for COMx- window, as shown next. The actual COM port number that is currently assigned to the modem replaces the x in COMx here. In our demo here, this window is for COM4. Thus, we see that our modem is currently assigned to COM4, although we wish to assign it to COM3.

7. Expand the COM Port Number Pop-up Combo Box

Do that by tapping / clicking the downward pointing arrow immediately to the right of the port number. We’ve drawn a purple arrow in the previous picture, pointing at this expander button in the previous picture. When you expand the list, you get a complete list of available COM ports that this modem may use, as shown in the next picture.

8. Tap / Click the Desired New Port number in the List

You may have to scroll up or down in the list to find the port you want. In our demo, we’re assigning our modem to COM3. So we tap COM3 in the list, as shown in the previous picture, pointed at by the purple arrow. This then collapses the expanded port list back down to a single entry in the -COM Port Number- field, showing the new port number we chose. We’ve changed our modem to COM3, as shown in the next picture.

9. Tap / Click the OK button on the Advanced Settings for COMx Window to Continue with How to Change COM Port on USB Modem

Doing so closes that window, and reveals once again the device configuration window for our modem, as shown next.

10. Press the OK Button on the Device Configuration Screen

This applies the new COM port assignment to the modem, and closes that window, once again revealing the Windows 10 Device Manager window, as shown in the next picture.

11. Exit the Device Manger Window

Exit either via its file->Exit menu item as shown in the previous picture, or by tapping / clicking its -Close- button, found in the top right corner of the window (the X button). Your COM port reassignment for the modem is now complete.

With the COM port successfully changed, we recommend that you close and restart any program(s) that use the modem, and, if necessary, change the COM port settings in said program(s) to match the port number we just set up.

12. Done with How to Change COM Port on USB Modem !

Related Posts to How to Change COM Port on USB Modem

Suggested Reading

References for How to Change COM Port on USB Modem

Revision History

• 2019-05-30: Added links and tags.
• 2019-04-27: Added tags.
• 2018-04-18: Revised post title and content for better keyword targeting.
• 2017-12-04: Originally published.

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Important

This topic is intended for Microsoft's mobile operator (MO) partners who can configure how Windows connects to their networks. If you are a customer who is experiencing Windows network connection issues, see Fix network connection issues in Windows.

Automatic connection management, introduced in Windows 8, makes connection decisions by looking at Ethernet, Wi-Fi, and mobile broadband interfaces. These decisions lead to automatic connect and disconnect actions on Wi-Fi and mobile broadband interfaces.

Note

Windows responds to Ethernet connections but does not automatically manage Ethernet connections.

This topic describes how Windows automatically manages physical wireless connectivity and does not consider these connections:

• Dial-up connections, such as modems

• Pure virtual interfaces, such as VPNs and tunneled IP connections

Connection management policies

Windows 8, Windows 8.1, and Windows 10 include a number of policies to control connection management. These policies are not exposed in the Windows user interface but can be configured by using the WcmSetProperty API or Group Policy.

Minimize simultaneous connections

This policy is configured using the fMinimizeConnections Group Policy. It is on by default for Windows 8, Windows 8.1, and Windows 10.

Versions of Windows before Windows 10, version 1809, build 17763.404

In Windows 8, Windows 8.1, and versions of Windows 10 before Windows 10, version 1809, build 17763.404, this policy is a boolean value that can be modified using either Group Policy or the WcmSetProperty API.

If this policy is disabled, the behavior is similar to that for Windows 7 in which each interface connects to the most preferred network in range, regardless of the connectivity state of other interfaces.

If this policy is enabled, Windows attempts to maintain the smallest number of concurrent connections that offer the best available level of connectivity. Windows maintains connectivity to the following networks:

• Any Ethernet network

• Any networks that were manually connected during the current user session

• The most preferred connection to the Internet

• The most preferred connection to the Active Directory domain, if the PC is joined to a domain

All remaining networks are soft-disconnected, as described in the next section. This is also used to evaluate available networks that are not connected. Windows will not connect to a new network from which it would immediately soft-disconnect.

Windows 10, version 1809, build 17763.404 and later

In Windows 10, version 1809, build 17763.404 and later, this value is an enumeration that is only available through Group Policy.

This policy setting determines if a computer can have multiple connections to the Internet, to a Windows domain, or to both. If multiple connections are allowed, the policy then determines how network traffic is routed.

If this policy is set to 0, a computer can have simultaneous connections to the Internet, to a Windows domain, or to both. Internet traffic can be routed over any connection, including a cellular connection or any metered network. This was previously the Disabled state for this policy setting in builds of Windows before Windows 10, version 1809, build 17663.404. This option was first available in Windows 8.

If this policy is set to 1, any new automatic Internet connection is blocked when the computer has at least one active Internet connection to a preferred type of network. The order of preference is as follows:

1. Ethernet
2. WLAN
3. Cellular

Ethernet is always preferred when connected. Users can still manually connect to any network. This was previously the Enabled state for this policy setting in builds of Windows before Windows 10, version 1809, build 17763.404. This option was first available in Windows 8.

If this policy setting is set to 2, the behavior is similar to when it is set to 1. However, if a cellular data connection is available, that connection will always stay connected for services that require a cellular connection. When the user is connected to a WLAN or Ethernet connection, no Internet traffic is routed over the cellular connection. This option was first available in Windows 10, version 1703.

If this policy setting is set to 3, the behavior is similar to when it is set to 2. However, if there is an Ethernet connection, Windows does not permit users to connect to a WLAN manually. A WLAN can only be connected (automatically or manually) when there is no Ethernet connection.

Soft disconnect

The soft disconnect policy works as follows:

Modem Manager Para Windows

1. When Windows decides that a network should no longer be connected, it does not immediately disconnect. Abrupt disconnections degrade the user experience without providing an appreciable benefit and are avoided when possible.

2. As soon as Windows decides to soft-disconnect an interface, it informs the TCP stack that the network should no longer be used. The existing TCP sessions will continue uninterrupted, but new TCP sessions will use this interface only if explicitly bound or if no other interface routes to the desired destination.

3. This notification to the TCP stack generates a network status change. Networking applications should listen for these events and proactively move their connections to the new network, if possible.

4. Windows then checks the traffic level on the interface every 30 seconds. If the traffic level is above a certain threshold, no further action is taken. This allows ongoing active use of the interface, such as from a file transfer or VoIP call, to avoid disruption.

5. When the traffic drops below this threshold, the interface will be disconnected. Applications that keep long-lived idle connections, such as an e-mail client, may be interrupted and should re-establish their connections over a different interface.

Initial connection

Windows automatically connects and then immediately soft-disconnects in one circumstance. When a PC first starts or resumes from standby, all interfaces simultaneously attempt to connect in order to ensure that the user obtains network connectivity as quickly as possible. If multiple interfaces successfully connect, Windows begins soft-disconnecting interfaces immediately.

Prohibit interconnect between domain and non-domain networks

This policy is off by default for Windows 8, Windows 8.1, and Windows 10. When this policy is enabled, Windows attempts to prevent a PC from being interconnected between a domain network and a non-domain network. Enterprise administrators may use this when they are concerned about potential security breaches using a multi-homed machine as an attack point.

This policy does not affect system behavior when all connected networks route to the domain or when no connected network routes to the domain.

Multiple wireless networks

Many Windows 8, Windows 8.1, and Windows 10 mobile devices have an external Internet connection available to them at all times, even when in range of their enterprise Wi-Fi networks. When this policy is enabled, users may freely connect to either their public mobile broadband network or to the enterprise’s private Wi-Fi network and switch between them at will. However, manually connecting one will automatically cause the other to disconnect immediately.

Ethernet

Because Windows 8, Windows 8.1, and Windows 10 cannot automatically connect Ethernet cables to or disconnect them from a PC, they can only enforce the policy by allowing or prohibiting wireless connections. When a PC has an Ethernet connection to the domain network, wireless networks that do not connect to the domain cannot be connected, and vice versa. Attempts to do so will result in the following error:

For PCs that have multiple Ethernet ports, Windows cannot prevent an interconnection that is created by physically connecting the PC to two different Ethernet networks.

Effect on soft disconnect

Because prohibiting interconnections is a security consideration, any disconnections that comply with this policy take effect immediately, even if there is ongoing activity. Users will experience a connectivity disruption when transitioning between public and corporate networks, even if the two networks overlap.

For example, a user engaged in a VoIP call over a mobile broadband network with a laptop docked to a corporate Ethernet connection will lose the call, although the app may be able to automatically recover over the new connection. If the policy was not enabled, Windows would instead soft-disconnect the mobile broadband connection by waiting for the call to complete. On the other hand, a VoIP call started over a corporate Wi-Fi network will not be disrupted when docked to the corporate network because both networks connect to the domain. The Wi-Fi network is disconnected after the call is completed.

Prohibit roaming on mobile broadband networks

This policy prevents Windows from connecting to mobile broadband networks that are in a roaming state. By default, this policy is disabled, and the user may choose to manually connect to a mobile broadband network while roaming or to enable automatically connecting to such a network. When this policy is enabled, the user cannot choose a roaming mobile broadband network from Connection Manager.

Install Modem Windows 7

Network preferences

When considering which multiple connections to maintain, Windows uses a number of traits to determine the preferred networks. This is used only when determining whether to maintain a connection to a given interface, not for routing. If a connected interface is not in the process of being soft-disconnected, routing is determined by the metric in the routing table. If the route metric is not specified manually, Windows will automatically assign a route metric based on the link speed of the adapter.

Connection priorities

Windows prioritizes connections in the following order:

1. Ethernet networks

2. Networks manually connected during the current user session Download game simcity buildit mod unlimited money.

3. Networks that connect to both the Internet and the Active Directory domain to which the PC is joined

4. Signal strength of the currently connected Wi-Fi network

5. The PC’s preferred network list

Even though the link speed influences routing behavior among currently connected interfaces, Windows does not make connectivity decisions based on the link speed or throughput of a network. It is not possible to configure Windows to change its connection preference between a mobile broadband network and a Wi-Fi network based on the current speed of the mobile broadband network. If both are connected, the user or a desktop app can change route metrics to influence routing preferences.

Signal strength

For Windows 8 and Windows 8.1, if Windows detects that the currently connected Wi-Fi network has very low signal strength, it may choose to connect a mobile broadband network (if permitted by policy) to avoid disrupting network connectivity. This helps to smooth the transition when a user is moving away from a wireless access point.

Windows does not disconnect a more preferred Wi-Fi network until the signal strength cannot maintain the connection. If signal strength improves, Windows may soft-disconnect the mobile broadband adapter.

Windows 10 does not use the Wi-Fi signal strength.

Preferred network list

In most situations, the preferred network list determines which wireless network profiles Windows will use to connect. Prior to Windows 8, this list applied to Wi-Fi networks only. In Windows 8, Windows 8.1, and Windows 10, it can also include mobile broadband networks.

Automatic generation

Windows 8, Windows 8.1, and Windows 10 automatically update the preferred network list based on user actions. Any manual connection or disconnection will update the network list so that the same behavior will occur automatically in the future.

The following user actions modify the preferred network list:

• Initially connecting to a network The new network is added to the network list. The user specifies whether the network will automatically connect in the future.

  • Connecting to a new Wi-Fi network for the first time makes the network the most preferred network in the list.

  • Connecting to a new mobile broadband network for the first time makes the network the least preferred network in the list.

• Manually connecting to a Wi-Fi network Any other Wi-Fi network in range that is higher on the list is moved below the newly connected network in the list. The user specifies whether the network automatically connects in the future.

• Disconnecting from a network Windows will not automatically connect to this network in the future. It remains on the network list in case the user modifies this setting in the future.

Device Manager Modems

Group Policy

Modem Manager Windows 10

Wi-Fi profiles created by Group Policy are at the top of the network list. The user may manually disconnect from these networks or manually connect to other networks, but these networks remain at the highest position on the network list until removed by Group Policy.

Carrier-provisioning metadata

Mobile broadband and Wi-Fi hotspot operators provide Windows with a series of mobile broadband and Wi-Fi profiles by using the ProvisioningAgent or msProvisionNetworks APIs.

When initially provisioned, the operator-created profiles are added to the top (Wi-Fi only) or bottom (if mobile broadband is included) of the existing network list. You cannot influence the position of the networks the user provisions in the network list. However, you can define the relative order of their networks in the network list.

The user’s actions may modify the network list between applications of provisioning metadata. When provisioning metadata is reapplied, your desired network order is restored. However, the reordered set of networks is moved to the lowest position to which the user had moved any of your networks.

The preference between networks in the provisioning metadata is determined by the following:

1. The optional priority attribute on each network profile

2. Media type (Wi-Fi is more preferred than mobile broadband)

3. Order specified in the XML file

Manual modification

Prior to Windows 8, the Wi-Fi preferred network list was accessible to the user through the Manage Wireless Networks control panel. Telemetry indicates that very few users ever accessed this functionality. Additionally, this user interface was tied to Wi-Fi only and could not incorporate preferences between Wi-Fi and mobile broadband.

Most users will not need to manually modify the network list. However, certain users or applications may find it necessary to do so.

User interface

To remove a profile from the preferred network list while it is in range, select and hold (or right-click) the network and choose Forget this network. A network that is not in range cannot be removed from the list through the user interface.

Win32 APIs

An application may create new profiles in the network list using the appropriate media-specific API:

• For Wi-Fi networks, use the WlanSetProfile function.

• For mobile broadband networks, use the IMbnConnectionProfileManager::CreateConnectionProfile method.

Linux Modem Manager

To modify the order of the network list, use the WcmSetProfileList function. We do not recommend using the WlanSetProfileList function, as it may disturb the position of mobile broadband profiles in the network list in unintended ways.

To delete profiles from the network list, use the appropriate media-specific API:

• For Wi-Fi networks, use the WlanDeleteProfile function.

• For mobile broadband networks, use the IMbnConnectionProfile::Delete method.

Command-line

A user or script may create new profiles in the network list by using the appropriate media-specific commands:

• For Wi-Fi networks, use the netsh wlan add profile command.

• For mobile broadband networks, use the netsh mbn add profile command.

The order of the Wi-Fi profiles in the network list may be modified using the netsh wlan set profileorder command. However, this is not recommended and can disturb the position of mobile broadband profiles in the list in unintended ways.

To delete profiles from the network list, use the appropriate media-specific commands:

• For Wi-Fi networks, use the netsh wlan delete profile command.

• For mobile broadband networks, use the netsh mbn delete profile command.

Conflict resolution

When multiple profiles exist for the same network, Windows 8 and Windows 8.1 use the following logic to determine which profile should be used:

Modem Missing Device Manager Windows 7

1. Profile Type

   1. Group Policy profiles are preferred over user-created profiles.

   2. All-user profiles are preferred over single-user profiles.

2. Interface Arrival The profile on the most recently installed interface will be used.