collection(application)和collection(physical) 1这两个是什么意思啊 2两次指明是键盘keyboard,有什么必要

Usage Page(generic desktop controls)
usage(keyboard)
collection(application)
usage page(keyboard/keypad)
usage minimum(224)
usage maximum(231)
...
collection(application)和collection(physical)
1这两个是什么意思啊
2两次指明是键盘keyboard,有什么必要