The Poly APV-63 EHS Ringer Cable (85R29AA, part 75010-01) provides an inbound call ring signal to Poly wireless headset bases connected to Avaya IP phones via the APV-63 adapter. Without this cable, the headset base may not detect incoming calls for remote auto-answer — the ringer cable bridges that signal gap so the headset can alert you to calls and answer them hands-free. It is a required component for certain Avaya phone deployments using the APV-63 Electronic Hook Switch adapter. Key Features Inbound Call Detection: Carries the ring signal from the phone to the headset base, enabling the wireless headset to detect and announce incoming calls. APV-63 Specific: Designed for use with the Poly APV-63 Electronic Hook Switch adapter in Avaya IP phone environments. Enables Hands-Free Auto-Answer: Part of the complete EHS solution that allows call answer and end directly from the wireless headset. Technical Specifications Specification Detail HP SKU 85R29AA Poly Part Number 75010-01 Function Inbound call ringer signal cable Used With Poly APV-63 Electronic Hook Switch Adapter Phone Compatibility Select Avaya IP phones (via APV-63)