I’m thinking about replacing an older pbx system with four lines in my small business with Asterisk and VOIP. The average speed for my cable connection is 2.13 Mbps up/ 439.50kbps down.
What codec would provide a good balance between bandwidth and business class sound quality while not affecting employee internet access and my low volume web server? Also, will VOIP work with faxes?
black6,
When talking about sound quality I would recommend using g711 (which uses 64kbps) and a separate internet connection (348/348 line) for VoIP it’s affordable or somehow assign higher priority for VoIP traffic on existing connection. Having people surfing/downloading/uploading using the same connection without prioritizing VoIP traffic, most probably will cause degrading sound quality especially when all four lines will be talking. And I would say ‘while emploee internet access is not affecting VoIP traffic’ instead of ‘while VoIP traffic not affecting employee internet access’ 
voip-info.org/wiki/index.php … onsumption
Another option is installing Digium card for external lines.
Well, that’s what I think I would do.
In general, VoIP is not very friendly with fax. You can find more about this here -> voip-info.org/wiki-Asterisk+fax