This document defines constants that can be interpreted by an application to identify the purpose and meaning of a data field in a HID report.
Usages are also used to define the meaning of groups of related data items. This is accomplished by the hierarchical assignment of usage information to collections.
Usages identify the purpose of a collection and the items it contains. Each Input, Output, Feature, and/or Collection data item within a Collection item can be assigned a purpose with its own usage item. Usages assigned to a collection apply to the items within the collection.