This document is the user manual for Jabra BIZ 2400 USB headset, which introduces the components, usage, and related features of the headset. It also provides guidance on wearing the headset, adjusting the volume, and using the mute function. The headset can be used for answering calls with PC softphones and supports certain specific network phones. The document also provides instructions for installing Jabra PC Suite and using Lync 2010.