https://www.cdw.com/product/epos-sennheiser-ploycom-cable-for-electronic-hook-switch/6389833
EPOS CEHS-PO 01 - electronic hook switch adapter for headset, VoIP phone - 1000750 - Headset...
Buy a EPOS CEHS-PO 01 - electronic hook switch adapter for headset, VoIP phone or other Headset Accessories at CDW.com
electronic hook switch