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A non-compressed codec, G711, will give the best voice quality, as no compression and decompression is required. This in turn makes this G711 less susceptible to packet loss, which even in small amounts will quickly degrade voice quality. Other codecs which use compression techniques consume less bandwidth, a good thing, but this compression process in itself lowers the voice clarity and introduces a delay. Additionally, compressed codecs are even more susceptible to packet loss. In addition G711 will maintain better quality with more latent connections, whereas compressed codecs' voice quality can quickly degrade as latency increase, as the chart below reflects.
Lately many telephone companies, such as NocTel, have started using G722, which is at least double the bandwidth and quality of G711. Using this new codec is known by many as "HD Voice" and provides superior quality conversations across the Internet.
CNAM DIP
Requesting a Caller ID Name (CNAM) when you have the phone number.
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