Cisco 8821 Administration Manual page 119

Maintenance
Metric change
Conceal Ratio is near or at zero,
but the voice quality is poor
Note Voice quality metrics do not account for noise or distortion, only frame loss.
Cisco Wireless IP Phone 8821 and 8821-EX Administration Guide for Cisco Unified Communications Manager
Condition
• Noise or distortion in the audio channel such as echo or audio
levels.
• Tandem calls that undergo multiple encode/decode such as calls
to a cellular network or calling card network.
• Acoustic problems coming from a speakerphone, hands-free
cellular phone or wireless headset.
Check packet transmit (TxCnt) and packet receive (RxCnt) counters to
verify that voice packets are flowing.
Voice Quality Troubleshooting Tips
109