Plantronics MDA220 Multi Device USB Adapter (for PC and Telephone)
Amazon.com: 504P USB Adapter for Plantronics and Addasound Headsets - by Global Teck Worldwide - Connects to Headset to PC, MAC, Lync, Skype & USB VoiP Phones - Mute, Volume and Quick
Plantronics USB Adapter, 2.5mm to USB for Mobile
Plantronics TR-11 Adapter | 88608-11 - Headsets Direct