 |
 |
 |
 |
| What is a call center? |
| How call center works through VOIP? Simple call center structure: |
| Typical |
| What is a Predictive Dialer? |
What I should do if I am getting voice distortion continuously? There are a variety of problems that can cause distortion. Users may report that calls sound "noisy", "dead", "hollow", "cavelike" or "tunnel-like", have echo, sound slightly distorted, sound robotic, or be very choppy or garbled (see also Packet Loss) Example audio file - "robotic": Example audio file - "choppy": Resolution Problem of voice break occur due to network congestion so
|
| What I should do if I am getting Echo Problem? Echo is often due to a mismatched hybrid (2 to 4 wire convertor) on the analog part of a telephony connection. Another source of echo is acoustic feedback from speaker to microphone of a telephone handset. Echo becomes a problem when combined with a significant amount of delay. For example, if an IP phone was connected over wide area IP network to a VoIP Gateway then the delay would be large – echo that occurred on the trunk side of the Gateway would be audible in the IP Phone. If a user reports an echo problem then the source of this problem is likely to be on the other end of the connection. Talker echo occurs when some proportion of the "talker's" voice is echoed back to the talker - i.e. the person speaking hears their own voice. Listener echo occurs when some proportion of the talker's voice is echoed from the listener's end of the connection and then a second echo occurs which causes some proportion of this signal to be reflected back to the listener. This results in the listener hearing an echo of the talker's voice. Convergence echo occurs at the start of a call, and results from the time taken for the echo canceller to "converge". Impact Talker echo can be very annoying. When coupled with low delay, echo can lead to "hollowness" whereas in the presence of high delay echo sounds like....echo. Example audio file - 25 milliseconds round trip delay: Example audio file - 200 milliseconds round trip delay: Example audio file - 400 milliseconds round trip delay: Resolution Generally Voice over IP Gateways incorporate a line echo canceller to remove or reduce the echo level from analog loops. If this is not functioning correctly, possible due the echo canceller being disabled, to mis-configuration of the signal levels , non-linearity in the speech path or an excessively high echo level then some residual echo may be present. To resolve echo problems it is necessary to identify both the source of the echo (i.e. a particular analog loop or line card) and check its balance or configuration and then to identify why the echo canceller is not adequately compensating for the echo. |
| Start or end word missing in my calls? If users report that the start and end of words are being “clipped” then this is typically due to the Voice Activity Detector in the VoIP hardware. Voice Activity Detectors are used for silence suppression in packet voice systems, for echo suppression in echo cancellers and for echo suppression or directional control in speakerphones. Clipping can be the result of the sound level settings in the VoIP hardware being incorrectly configured. Impact Users report that words are being clipped - similar in effect to a lower quality speakerphone. Resolution If VAD or Silence Suppression is being used then you may wish to disable this until the loss plan has been verified. If VAD/Silence Suppression is not being used then the problem may be located in the Echo Canceller in a Voice over IP Gateway. |