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Collaboration, Voice & AV · Foundational

G.711

The ITU-T uncompressed PCM voice codec at 64 kbps, using mu-law or A-law companding and 8 kHz sampling.

Definition

G.711 provides narrowband (300 to 3400 Hz) toll-quality audio with a MOS of about 4.1 and minimal algorithmic delay. It is supported by virtually every voice device and is the default for LAN calls and TDM interworking, and it reliably carries fax and modem tones in passthrough. With 20 ms packetization over Ethernet a G.711 call consumes roughly 87.2 kbps per direction.

Example

Two IP phones on the same campus negotiate G.711 mu-law because the intra-region bit rate allows 64 kbps.

Exam tip

Know the numbers: 64 kbps payload, about 80 kbps at Layer 3 and 87.2 kbps on Ethernet with 20 ms packets.

Don't confuse it with

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