Plantronics Vista Plus DM15 digital adapter utilizes 2nd generation technology and DSP (digital signal processing) to deliver unsurpassed levels of acoustic protection and exceptional sound quality. With Sound Guard DIGITAL, daily personal noise exposure is monitored and automatically controlled to aid compliance with new EU legislation. Constantly on guard, Sound Guard DIGITAL also identifies and eliminates sudden loud sounds, to avoid user discomfort. Plantronics Call Clarity DIGITAL combines a range of techniques to enhances sound quality. It\'s automatic volume leveler maintains a constant listening volume, regardless of incoming call loudness. Selective frequency-response shaping maximizes speech intelligibility, whilst phone-line noise is also reduced. Product Features Sound Guard DIGITAL acoustic protection: Anti-startle processing to remove sudden, loud sounds. Daily personal noise exposure control. Call Clarity DIGITAL for optimum sound quality: Enhanced speech intelligibility with selective frequency-response shaping. Phone-line noise reduction. Automatic Volume leveller. Volume, mute and tone controls. Compatible with all major business phone systems Compatible with all Plantronics Call Centre and Office headsets Headset / handset switch