What Is G.711?
G.711 is the ITU-T standard audio codec for telephony, using 64 Kbps per direction at 8 KHz narrowband quality. It is the baseline codec supported by every VoIP / ISDN / PSTN system.
Definition
G.711 has two flavors: G.711 ulaw (North America, Japan) and G.711 alaw (Europe, Asia, including Thailand). Both sample at 8 KHz, 8-bit, yielding 64 Kbps.
Usage
Default codec on most IP phones, IP PBX, and SIP Trunks. Quality is good and uncompressed, so CPU usage is low, but bandwidth is the highest among common codecs.
Related Concepts
Other codecs compress more: G.729 (8 Kbps), Opus (6-510 Kbps). G.711 still serves as the audio quality benchmark.
Frequently Asked Questions
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