Yealink QD to RJ9 Cord for YHS Series of Corded QD Headsets Compatible with Third-Party Phones The QD-RJ9-CORD-3PTY is a Quick Disconnect (QD) to RJ9 cord for Yealink YHS34, YHS34 Lite, and YHS36 headsets for easy connection with Cisco 79xx IP Phones and Avaya callmaster V and VI. Yealink Headset Compatibility Guide Use Yealink's headset compatibility guide to find which Yealink headsets are compatible with which device - from a variety of manufactures! Yealink Headset Selling Tool Download Yealink's headset selling tool reference guide, highlighting which Yealink headsets are best suited to which scenarios.