Dorie Osborn 2002-1-21 2005-2-9 Plantronics headset adapters and amplifiers 56330 text/html 1.0 EN Plantronics S20 Model Headset Adapter A20 Model Headset Adapter P10 Plug Prong Adapter M12 Vista Telephone Headset Amplifier Amplifier Adapter Headset Headset Adapters & Amplifiers text