Amazon.com: USB-A to QD Adapter Cable Compatible with Any Plantronics or TruVoice Wired Headset with a QD and Includes Volume Control and Mute Functionality (Connects Headset to PC, Laptop and Softphones) :
Plantronics CS540 (C054) Wireless Headset Setup Guide- WITH Headset Port - YouTube
USER MANUAL Plantronics CS540 Wireless Headset System | Search For Manual Online
APS-1/APS-10/APS-11 (EHS Cable): How to Install on a Siemens Optipoint Phone | Poly, formerly Plantronics & Polycom
Plantronics CS545-XD Wireless Headset - VoIP Supply