The Agent 2.5mm to PLX QD Cable is a bottom lead designed to connect an Agent corded headset (which has a Quick Disconnect, or QD, end) to a desk phone or cordless phone with a 2.5mm headset jack. This cable is often identified by model numbers like BL-06(P) or PL28-0056 and is compatible with Plantronics-style (PLX) Quick Disconnect connections. The QD feature allows the user to quickly detach the headset and walk away from their desk without dropping a call, effectively putting the call on hold at the QD point. It is a simple, plug-and-play accessory crucial for using professional-grade headsets with specific telephone systems, including certain models from Cisco, Polycom, and Grandstream, as well as many standard cordless phones.