Plantronics 3.5mm to Quick Disconnect Adapter for iPhone, Android and Other Smartphones, Cisco 8821
Plantronics DA80 USB to Headset Adapter (201852-01)
Amazon.com: 2.5mm Jack to QD Bottom Adapter Cable - Plantronics Alternative to fit Phones with 2.5mm Headset Connection for Cisco SPA303,501G,502G 504G,508G,Cisco Linksys SPA921 922,etc : Electronics