Headset Interface Adapter - Lets you easily place an audio-only call with SoundStructure installed audio solutions. | Poly, formerly Plantronics & Polycom
Headset Adapters for Polycom IP Phones
Polycom Electronic Hook Switch Control (APP-5) Adapter
Amazon.com: U10 Adapter Compatible with Any Plantronics or TruVoice Quick Disconnect (QD) Headset for All Cisco 6000, 7800 and 8000 Series Phones and Models 7931 7940 7941 7942 7945 7960 7961 7962 7965 7970 7975 : Electronics
VT EHS13 for Polycom( to DHSG) and VT/Jabra DECT headsets
How to configure Polycom VVX410 with Plantronics CS520 and EHS APP-51 – ProVu Blog
PLANTRONICS HW510-POLY Polycom IP Phone Compatible Headset