Plug Prong for PBX and ACD Systems. Allows PBX and ACD users to use the full range of Plantronics headsets. Just plug the P10 into your operator console and you are ready to enjoy the comfort and convenience of Plantronics. Volume and automatic gain controls let you adjust incoming calls to a listening level that's comfortable. Easy to install and very durable. Includes the handy Quick-Disconnect feature and 10-foot coil cord.