There are two varieties of the G.711 codec, namely U-law and A-Law. U-law is typically used by North America and Japan, whilst A-law is typically used by the rest of the world.
G.711 will give great call quality for VoIP as it does not compress packets, and as a result, the call will sound like a regular ISDN call. This Codec is supported by most VoIP providers.
For any specific codec requirements please get in touch with our support team.