Voice quality is an issue that is sometimes forgotten in the race to save as much money as possible. Mytel believe that at some point call quality becomes less than acceptable for a number of reasons.

The choice of compression codec effects bandwidth usage and the call quality. The choice of codec and quality of your internet service provider account (in terms of upload and download speed and packet routing) can affect your call quality. Once the call is delivered to our network the way we deliver the call to its destination can also affect your call quality. We use one method of call termination for Australian landlines / mobiles and another for international calls. Both of these termination methods provide business grade call quality. We have cheaper call termination methods available to us however these do not provide business grade voice quality.

The industry standard for measuring voice quality is as a Mean Opinion Score (MOS) on a scale from 1-5 where 1 is the lowest and 5 the highest. Telco-grade voice refers to MOS scores of around 4.0-4.2.

If your broadband connection suffers from congestion or you share it with others who download large files you may get a MOS score in the range of 3.0-3.5. Delivering a call onto the Mytel network that is already degraded to 3.0-3.5 isn't going to improve your call quality back to telco grade. So, in those circumstances you wouldn't benefit from our business grade VoIP.

It's possible to get a MOS score of 4.1-4.4 with a G.711 codec (operating at 64 Kbps) however that will chew up your download quota quickly and could more easily be affected by glitches in the download speed such as traffic blockages at your exchange, etc.

Using a low band width codec such as G.729 (operating at 8 Kbps) it's still possible to achieve a MOS score of 3.9 from your IP device to the network. The difference between a traditional call and a VoIP call at a MOS of 3.9 would be virtually indiscernible to most of us.

To test the quality of your connection for VoIP go to www.testyourvoip.com and select "Sydney" from the network call destination list.

Summary

So, in summary, you can expect to receive call quality as good as normal telco voice calls using the Mytel network if your broadband connection doesn't limit your MOS score.