Versions supported

  • For point-to-point solutions, for example, a USB keyboard or mouse interfaced to an embedded system, the firmware that operates the MAX3421E can be simple since only a targeted device is supported. Internal level translators allow the SPI interface to run at a system voltage between 1.4V and 3.6V.
  • The CANBUS USB adapter connects a CANbus to the USB port of a PC or notebook, which also supplies the power to the adapter (no power supply needed). In the downloads section now you can find all the related drivers and software applications and even Windows 7 64-bit kernel driver, which was added recently.

Send your device, along with a note explaining the reason, the details of the person to whom the quote should be sent (email address or fax n°) and shipment address, to: Depisteo Customer Service 112 Skyline Drive Arlington, WI53911 USA. Upon receipt, our After Sales Service will carry out expertise on your device and send you a quote for. The driver is loaded based on a compatible ID match similar to other USB device class drivers included in Windows. USB Class02&SubClass02. 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.

  • 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.


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.

Srs medical usb devices drivers



  • 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.


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 this KB article.

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:

  • '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.

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.

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:

Srs Medical Usb Devices Driver Vga

  • 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:

Related topics

USB or Universal Serial Bus is the most common and popular interface for connecting variety of devices to computer and it is also the fastest way to transfer huge amount of data from one device to another. We all use USB in our daily life and work whether it is in computers, smartphones, tablets, camera etc. There are various types of USB connectors and ports, in computers we see a larger USB port, in smartphones a tiny one and in printers, scanners and camera a different one. Now here comes new type of USB physical connector / port that is just been released known as USB Type-C, but first let us learn about the various older types of USB ports / connectors.


  • 1 Types of USB Ports & Connectors
  • 2 USB Type-C Explained in Detailed
    • 2.1 Advantages & Benefits of USB Type-C

Types of USB Ports & Connectors

Srs Medical Usb Devices Drivers

Here are various USB types:

USB Type-A: Most popular USB Type that is found in computers, laptops and netbooks. It has the biggest size as compared to other USB types.

USB Type-B: They are generally found in printers, scanners etc. USB Type-B is further divided in three sub-types that being mentioned below:

  • Mini-B: Generally found in SLR Digital cameras, scanners etc.
  • Micro-B: They are widely used in smartphones, tablets and other small or mobile devices. Can also be seen in small digital cameras.
  • Micro-B USB 3.0: Found in high speed USB 3.0 external Hard disks and some other high speed devices.
  • Standard-B USB 3.0: In printers, scanners etc.

USB Type-C: The newest USB standard which is currently available in few devices but in future it will replace all other USB-Types in every device.

USB Versions / Revisions

RevisionMaximum SpeedMax. Power OutputPower Direction
USB 1.112Mbps2.5V, 500mAHost to peripheral
USB 2.0480Mbps2.5V, 1.8AHost to peripheral
USB 3.05Gbps5V, 1.8AHost to peripheral
USB 3.110Gbps20V, 5A (100 Watt)Bi-directional, can provide and receive power using the same port

USB Type-C Explained in Detailed

USB Type-C is the latest USB standard that is set to replace all the other USB Types in the future. The need for new USB Type arises because of the limitations of the other USB types whether it is in terms of speed, power output or size. USB Type-C port and connector is very small in size, yet it is very powerful of all other USB types. You can put a USB Type-C port in virtually any device whether it is a PC, Laptop Smartphone, Tablet or any other smaller mobile device.

Apple MacBook 2015 USB Type-C Port

Advantages & Benefits of USB Type-C

Here are main advantages or benefits of USB Type-3.

Smaller in Size

The first advantage of USB Type-C port or plug is that it is very small in size which means it will take less space on your devices. The size of a USB Type-C port is almost the same as that of a micro-B USB port but it is much powerful and advanced than a micro-B USB port.

Reversible Plug Orientation

USB Type-C has reverse plug orientation which means you can plug any USB Type-C connector end to any of the USB Type-C port in your devices. Also you don’t have to worry about plugging the USB Type-C connector upside or upside down as there is no given orientation to plug in a USB Type-C connector to a USB Type-C port, whereas in other USB Types there is a proper orientation and you have to put in a USB connector in only one orientation otherwise it will not go in or it may break.

Supports up to USB 3.1

As of now USB Type-C supports up to the latest USB 3.1 specification. This means if you have a high speed USB Type-C port in your computer or smartphone then you can enjoy data transfer speed up to 10Gbps. Well one thing to note here is that not all USB Type-C ports are USB 3.1 ready and it depends on the manufacturer what underlying technology (USB 2.0 / USB 3.0 / USB 3.1) they have implemented for the USB Type-C port in their device. We have seen this in past because Nokia N1 Tablet had USB Type-C port but it was only USB 2.0. But because we are moving to the future and not past we expect that the majority of upcoming devices with USB Type-C port will be USB 3.1 ready only.

Power Delivery (PD)

USB Type-C can deliver much greater amount of power as compared to all other USB Types. The maximum power output for USB Type-C port is 100W (20V X 5A) which can be used to charge bigger devices also, which includes Laptops, Netbooks etc. Also the direction of power in USB Type-C port is two ways or Bidirectional which means it can give and receive power through a single port only. This can bring a revolution in the area of battery charging because now we will be able to charge our laptops through a USB Type-C port only, and we do not require or have to carry those bulky power adapters and chargers. But it must be noted that for charging a bigger device, the Device (Laptops, Netbooks etc.) and USB Type-C Cable both must support Power Delivery (PD) feature.

One Cable for All

For devices with USB Type-C ports you only require one type of cable which has USB Type-C connectors on both the ends. You don’t have to use any conversion type cables anymore and only one cable is required for connecting all your devices having USB Type-C ports.

Backward Compatible (using adapters)

If you want to plug in your device having older USB Type in a computer with new USB Type-C port then you can do so by using Type A to Type C or Type A to Type C adapters and cables. Your device will work but it will not get the maximum performance which you can get with a device having the USB Type-C port.

USB Type-C to Type-A Female Cable

List of Devices with USB Type-C Port

Here is the list of laptops, tablets, hard drives and smartphones that comes with USB Type-C Port.

Nokia N1 Tablet

Apple MacBook 2015

Google’s second Chromebook Pixel

HP Pavilion X2 10.1-inch Detachable 2 in 1 Laptop

OnePlus 2 (Android Smartphone)

Xiaomi Mi 4c (Android Smartphone)

Xiaomi Mi5 (Android Smartphone)

Samsung Galaxy 7 (Android Smartphone)

Nexus 6P (Android Smartphone)

OnePlus X (Android Smartphone)

Nexus 5X (Android Smartphone)

ASUS ZenFone 3 (Android Smartphone)

Gionee Elife S Plus (Android Smartphone)

Xiaomi Mi Pad 2 (Android Tablet)

Xiaomi Mi5 (Android Phone)

Microsoft Lumia 950 & 950 XL (Windows Phone)

Xiaomi Redmi Note 3 (Android Smartphone)

Nexus 5X (Android Smartphone)

Meizu Pro 5 (Android Smartphone)

UMI Hammer S (Android Smartphone)

LeEco Le 1S (Android Smartphone)

Gionee Elife S8 (Android Smartphone)

Google Pixel C (Chromebook)

Gigabyte GA-Z170X-Gaming 6 Motherboard

SanDisk SSD’s (USB Type-C series only)

LaCie mobile drive (external hard disk)

Google Pixel C Tablet (Android Tablet)

iPad Pro

Coments are closed
Scroll to top