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Microsoft MOS Calculations

Endpoints that support VoIP and video quality metrics in a Microsoft system provide the following types of MOS:

• Listening quality MOS (MOS-LQ): Isolates the listening quality of audio by excluding bidirectional effects, such as delay and echo.
• Conversational quality MOS (MOS-CQ). Consists of the listening quality in each direction of the call, taking into account impairments from delay and echo.
• Network MOS: MOS listening quality value that is based only on network factors, such as codec, packet loss, packet reordering, packet errors, and jitter. Generally, the Lync instances report these values and other quality metrics at the end of each call. The Network MOS therefore helps you isolate network impediments on audio quality.

The proprietary Microsoft codecs, RTAudio and Siren (used for conference calls), can operate in two bandwidth modes. Therefore, MOS-LQ and Network MOS are reported on a wideband scale.