This allows to use Yosemite compatible USB devices, such as Avid/M-Audio Fast Track Ultra USB soundcard, with ElCapitan.
This is a IOUSBHostFamily.kext from a clean install of ElCapitan 10.11.5 with following modifications :
removed AppleUSBEHCI.kext, AppleUSBEHCIPCI.kext, AppleUSBOHCI.kext, AppleUSBOHCIPCI.kext, AppleUSBUHCI.kext, AppleUSBUHCIPCI.kext, AppleUSBXHCI.kext, AppleUSBXHCIPCI.kext from Plugins folder.
added previous Yosemite versions of AppleUSBEHCI.kext, AppleUSBOHCI.kext, AppleUSBUHCI.kext, AppleUSBXHCI.kext (taken from IOUSBFamily.kext Plugins folder, from a clean install of Yosemite 10.10.5) inside Plugins folder.