MB Interface Terms

The following terminology is used throughout the Mobile Broadband (MB)documentation:

Term Description


Mobile Broadband Interface Model, a USB Device Working Group (DWG) specification for mobile broadband devices.

MBIM function

A USB function within a USB device that is compliant with the MBIM specification.

Mobile broadband device

A USB device that is either single function or multi-functional. In the single function case, the function should be an MBIM function. In the multi-function case, one of the functions is the MBIM function. This may also be a multi-configuration device in which at least one of the configurations contains the MBIM function.


The earlier name for the MBIM specification. Some diagrams still refer to the MBIM functions as NCM2 functions.

Virtual CD-ROM

A CD-ROM function that does not have a physical CD-ROM drive.


Interface association descriptors (IADs) used to group interfaces into functions.


Union function descriptors (UFDs) described in the Wireless Mobile Communication (WMC) specifications. UFDs are used to group interfaces into functions. This is an alternative to using IADs.


The ability of a USB device to expose a different set of USB functions than what is currently exposed.


Software required by Windows to work with a USB function.

Inbox driver

A driver supplied by Microsoft for USB functions. These drivers are present in Windows.

IHV driver

A driver supplied by the independent hardware vendor (IHV) for USB functions that do not have inbox drivers.

IHV driver package

A collection of all IHV drivers supplied by the IHV.


A Microsoft USB hub driver.


A Microsoft driver for USB composite devices.


Mobile Broadband Class Driver, the inbox driver in Windows 8 for USB functions that conform to the MBIM specification.