I'm working on a Composite USB device with HID + CDC device classes in one device. Things are not working 100% as yet, but irrespective op the details of my project, I just have a simple question.

Does a Composite USB devices show up as a single device os as multiple devices when plugged into a PC?

In other words, how many devices should my CDC + HID device show up as, in for example the Windows Device Manager, or my Mac's System Information?


1 Answer 1


Here's what my device manager looks like when set to "View -> Devices by connection":

enter image description here

As you can see, the generic "USB Composite Device" and "Sierra Wireless HSPA Device" each get broken down into distinct endpoints. The Sierra Wireless device has multiple CDC endpoints and a network adapter.

In the normal view of device manager, it just shows the endpoints and not the intermediate composite devices or hubs.

However, if you have a composite device but have not installed its driver, it shows as one device of type "unknown".

  • \$\begingroup\$ Same on a mac.. \$\endgroup\$
    – Passerby
    Jul 22, 2013 at 16:50

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