HP Poly APU-76 Electronic Hook Switch Adapter for Headsets - TAA CompliantExtend the wireless freedom of DECT and 900 MHz headsets to your UC system and manage softphone calls with any CS500 Series or CS500 XD Series headset. The APU 76 provides PC connectivity with one touch call control across a wide array of softphones and provides plug and play compatibility with Microsoft Skype for Business. To find out if this cable works with your softphone, visit the Plantronics Compatibility Guide. This cable also works with Mitel