USB

[rckanta]

What are the difference between the USB protocol and USBMS protocol?
When do we need to use USB protocol and USBMS protocol?

Thank you for your help.

[ataradov]

USBMS is not a standard acronym for anything. What specific protocol you are referring to?

The only thing that comes to mind for USB MS is Mass Storage.  If this is what you are talking about, then MS is not a protocol, it is a specific profile (set of commands)  for storage devices.

[Doctorandus_P]

If this is indeed from "Mass Storage", then it's just one of the sub protocols for USB.

There are many of them, some common examples:
HID = Human Interface Device, which is used by all keyboards and mice.
CDC = Communications Device Class, used for example for those serial port dongles on USB.

And there are many other sub protocols for USB.

[Bassman59]

What are the difference between the USB protocol and USBMS protocol?
When do we need to use USB protocol and USBMS protocol?

Thank you for your help.

Assuming you mean USBMSC and not just USBMS --

USB is the overarching standard. It defines the bus and the basics of transactions.

ALL USB Devices conform to a Class. There are several defined USB Device Classes. There is also a Vendor Defined class, which lets you implement a device that meets your needs if none of the existing Standard Classes work.

The reason for this is so that users can just plug their device into their computer and if the device conforms to a standard Class then the computer will recognize it, use the correct drivers, and then the thing just magically works.

USBMSC or "USB Mass Storage Class" is one of the pre-defined USB Classes.