With the Sennheiser UI770 Universal Interface Amplifier, you can easily switch between the headset, handset and PC, adjust the volume of the headset speaker and mute the headset microphone. The UI770 is the ideal universal wideband Interface box that lets you switch directly between handset and headset, and between phone and PC. Connect a PC, standard phone, handset, a headset of the Sennheiser contact center or office series and even a dictaphone for voice recording. The UI770 supports the possibility of limiting the speaker volume by simply setting a switch. This secures compliance with the Noise of work Directive from EU (EU Directive 2003/10/EC) and will result in a reduced maximum output level for the user. Features: Dynamic Volume control keeps incoming calls at the same sound level and prevents sudden noises Sound clarity system reduces background noise and enhances the caller's voice Compatible with both wideband and narrowband headsets and phone systems Easy switching option between headset and handset as well as between phone and PC Integrated dictaphone interface for economical and easy call recording Complies with EU Noise at work Directive with a single switch Automatic power save function Dimensions: 1.3" x 3.6" x 4" (32mm x 91mm x 101mm) Includes: UI770 interface box 1.5 volt C-size battery Telephone connecting cable (RJ9 4/4) Modular to easy disconnect cable (headset bottom cable)