Versions supported
In order to test any application or emulator create two virtual serial ports COM3 and COM4 with Virtual COM Port Driver and connect them in a pair via virtual null modem cable. All data sent by the first application to virtual serial port COM3 will be received on virtual serial port COM4, and all data sent to virtual serial port COM4 will be. Modprobe gserial Windows should recognize the gadget serial device and ask for a driver. Tell Windows to find the driver in the folder that contains the linux-cdc-acm.inf file. For example, on Windows XP, when the gadget serial device is first plugged in, the 'Found New Hardware Wizard' starts up. Drivers for the Plugable USB serial adapter using an authentic Prolific chipset, model PL2303-DB9. The version driver (ser2pl.sys or ser2pl64.sys) should be something like 3.6.78.350. But this one doesn't work anymore with old PL-2303 hardware. Sometimes, installing the latest version of drivers solve the problem, but in this case, this is the opposite. The latest version doesn't work anymore with old hardware, and you need to downgrade the. The driver should be provided by whoever makes the specific adapter you're using. It is certainly the case that adapters from multiple vendors sometimes use the same chipset internally (FTDI is a popular choice for USB to serial interfaces) and therefore the same driver might work on adapters from multiple vendors, but that isn't a guarantee.
- Windows 10
- Windows 8.1
Applies to
- Device manufacturers of CDC Control devices
Microsoft-provided in-box driver (Usbser.sys) for your Communications and CDC Control device.
In Windows 10, the driver has been rewritten by using the Kernel-Mode Driver Framework that improves the overall stability of the driver.
- Improved PnP and power management by the driver (such as, handling surprise removal).
- Added power management features such as USB Selective Suspend.
In addition, UWP applications can now use the APIs provided by the new Windows.Devices.SerialCommunication namespace that allow apps to talk to these devices.
Usbser.sys installation
Load the Microsoft-provided in-box driver (Usbser.sys) for your Communications and CDC Control device.
Note
If you trying to install a USB device class driver included in Windows, you do not need to download the driver. They are installed automatically. If they are not installed automatically, contact the device manufacturer. For the list of USB device class driver included in Windows, see USB device class drivers included in Windows.
Windows 10
In Windows 10, a new INF, Usbser.inf, has been added to %Systemroot%Inf that loads Usbser.sys as the function device object (FDO) in the device stack. If your device belongs to the Communications and CDC Control device class, Usbser.sys is loaded automatically.You do not need to write your own INF to reference the driver. The driver is loaded based on a compatible ID match similar to other USB device class drivers included in Windows.
USBClass_02
USBClass_02&SubClass_02
- If you want to load Usbser.sys automatically, set the class code to 02 and subclass code to 02 in the Device Descriptor. For more information, see USB communications device class. With this approach, you are not required to distribute INF files for your device because the system uses Usbser.inf.
- If your device specifies class code 02 but a subclass code value other than 02, Usbser.sys does not load automatically. Pnp Manager tries to find a driver. If a suitable driver is not found, the device might not have a driver loaded. In this case, you might have to load your own driver or write an INF that references another in-box driver.
- If your device specifies class and subclass codes to 02, and you want to load another driver instead of Usbser.sys, you have to write an INF that specifies the hardware ID of the device and the driver to install. For examples, look through the INF files included with sample drivers and find devices similar to your device. For information about INF sections, see Overview of INF Files.
Note
Microsoft encourages you to use in-box drivers whenever possible. On mobile editions of Windows, such as Windows 10 Mobile, only drivers that are part of the operating system are loaded. Unlike desktop editions, it is not possible to load a driver through an external driver package. With the new in-box INF, Usbser.sys is automatically loaded if a USB-to-serial device is detected on the mobile device.
Windows 8.1 and earlier versions
In Windows 8.1 and earlier versions of the operating system, Usbser.sys is not automatically loaded when a USB-to-serial device is attached to a computer. To load the driver, you need to write an INF that references the modem INF (mdmcpq.inf) by using the Include directive. The directive is required for instantiating the service, copying inbox binaries, and registering a device interface GUID that applications require to find the device and talk to it. That INF specifies 'Usbser' as a lower filter driver in a device stack.
The INF also needs to specify the device setup class as Modem to use mdmcpq.inf. Under the [Version] section of the INF, specify the Modem and the device class GUID. for details, see System-Supplied Device Setup Classes.
For more information, see How to use or reference the Usbser.sys driver from universal serial bus (USB) modem .inf files.
Configure selective suspend for Usbser.sys
Starting in Windows 10, Usbser.sys supports USB Selective Suspend. It allows the attached USB-to-serial device to enter a low power state when not in use, while the system remains in the S0 state. When communication with the device resumes, the device can leave the Suspend state and resume Working state. The feature is disabled by default and can be enabled and configured by setting the IdleUsbSelectiveSuspendPolicy entry under this registry key:
To configure power management features of Usbser.sys, you can set IdleUsbSelectiveSuspendPolicy to:
Driver monitor acer al1716 windows 7. '0x00000001': Enters selective suspend when idle, that is, when there are no active data transfers to or from the device.
'0x00000000': Enters selective suspend only when there are no open handles to the device.
Gadget Serial (com4) Driver Windows 7
That entry can be added in one of two ways:
Write an INF that references the install INF and add the registry entry in the HW.AddReg section.
Describe the registry entry in an extended properties OS feature descriptor. Add a custom property section that sets the bPropertyName field to a Unicode string, 'IdleUsbSelectiveSuspendPolicy' and wPropertyNameLength to 62 bytes. Set the bPropertyData field to '0x00000001' or '0x00000000'. The property values are stored as little-endian 32-bit integers.
For more information, see Microsoft OS Descriptors. Inq1 nmea device (com8) driver download for windows 10.
Develop Windows applications for a USB CDC device
If you install Usbser.sys for the USB CDC device, here are the application programming model options:
Starting in Windows 10, a Windows app can send requests to Usbser.sys by using the Windows.Devices.SerialCommunication namespace. It defines Windows Runtime classes that can use to communicate with a USB CDC device through a serial port or some abstraction of a serial port. The classes provide functionality to discover such serial device, read and write data, and control serial-specific properties for flow control, such as setting baud rate, signal states.
In Windows 8.1 and earlier versions, you can write a Windows desktop application that opens a virtual COM port and communicates with the device. For more information, see:
Win32 programming model:
.NET framework programming model:
Gadget Serial (com4) Driver Download
Related topics
Click OK, and if Windows warns you about a duplicate, ignore the warning and click Yes. Click OK and then OK to the port settings. Then close the Device Manager window. If you want to confirm the port change has indeed been made, click on Device Manager again and check the listed Ports. Now close the System Properties window.
At this point, you are ready to use the virtual COM port in any application!
Note that, if you unplug the USB device and plug it back in later, Windows will still remember the COM port assignment, so you won't need to go through this procedure again. However, there is a known Windows issue that affects most applications. The virtual COM port will be removed from the device manager when the USB cable is unplugged, even if an application has the virtual COM port open. The virtual COM port will not be accessible even after the virtual serial device is reconnected unless the virtual COM port is released by the application prior to the reconnection, which may require closing the application first. It is therefore recommended that the application be closed before the USB device is unplugged.