What is G.722?

G.722 is an ITU-T standard wideband audio codec that samples voice at 16 kHz and encodes a 50 Hz to 7 kHz frequency range — roughly double the bandwidth of the traditional G.711 narrowband codec used on legacy telephony. The result is the noticeably clearer “HD Voice” quality that modern VoIP calls between supported endpoints can deliver, at the same 64 kbps as G.711.

How G.722 works

G.722 uses sub-band ADPCM (Adaptive Differential Pulse Code Modulation): it splits the input audio into a lower and an upper sub-band, applies adaptive quantisation to each, and produces a single bitstream. Three rate modes exist — 64, 56, and 48 kbps — though the 64 kbps mode is by far the most common deployment.

The encoder runs in real time with very low computational cost, which is why G.722 appears on hardware desk phones, softphones, and gateways at no meaningful overhead versus G.711.

G.722 vs. G.711 vs. Opus

The three codecs cover most production voice traffic and serve different sweet spots:

• G.711: narrowband 300 Hz to 3.4 kHz at 64 kbps. The historical PSTN standard. Crystal clear at toll quality but bandwidth-limited — every consonant in “Sox” and “Fox” sounds the same.
• G.722: wideband 50 Hz to 7 kHz at 64 kbps. Audibly clearer with no bitrate penalty. Universally supported by modern endpoints.
• Opus: super-wideband and fullband (up to 20 kHz) at variable bitrates from 6 to 510 kbps. The default in WebRTC, with the best speech and music quality at moderate bitrates.

When both endpoints support it, G.722 has effectively replaced G.711 inside modern VoIP networks. Opus dominates browser-based calling. The gateway to the PSTN typically transcodes back to G.711 because legacy carrier networks do not carry wideband.

What “HD Voice” actually means

“HD Voice” is a marketing label applied to any wideband or super-wideband codec — most commonly G.722 on the enterprise side and AMR-WB on the mobile side (used for VoLTE and VoNR). The audible difference vs. G.711 is significant: fricatives, sibilants, and background detail come through cleanly, and call fatigue on long meetings drops noticeably. Both endpoints must support and negotiate the wideband codec; a single legacy hop in the path forces the call back to narrowband.

Where G.722 fits in a modern deployment

• On-net business calls: nearly every modern desk phone, softphone, and PBX supports G.722; calls between internal extensions ride it by default.
• SIP trunking carrier hops: support varies — premium carriers can carry G.722 end to end, others transcode to G.711 at the boundary.
• Gateway to the PSTN: typically a forced G.711 transcode, because the PSTN is narrowband.
• Conferencing bridges: most mix in wideband internally to maintain quality across multiple participants.

The right operational target is “wideband end to end whenever possible, with a clean fallback to narrowband at unavoidable hops.” That maximises perceived quality without breaking interop.

G.722 frequently asked questions

What does G.722 mean?

G.722 is the ITU-T recommendation number for a wideband audio codec for 7 kHz audio coding at 64 kbps. It is what most enterprise VoIP deployments use to deliver the perceptibly clearer “HD Voice” call experience compared to the older narrowband G.711.

What is the difference between G.722 and G.711?

G.711 is a narrowband codec (300 Hz to 3.4 kHz) used on the legacy phone network. G.722 is a wideband codec (50 Hz to 7 kHz) at the same 64 kbps bitrate, delivering noticeably clearer voice. Both endpoints must support G.722 for the call to ride wideband end to end.

Is G.722 the same as HD Voice?

“HD Voice” is a marketing label for any wideband or super-wideband codec. On the enterprise VoIP side, G.722 is the most common HD Voice codec. On mobile (VoLTE and VoNR), AMR-WB plays the same role. Both deliver the audible step up from narrowband G.711.

What is the bitrate of G.722?

G.722 operates at 64 kbps in its standard mode — the same bitrate as G.711 — with lower 56 and 48 kbps modes available but rarely used. The 64 kbps mode delivers the highest quality and is the default on nearly every supported endpoint.

See how DialPhone fits

DialPhone’s business phone negotiates G.722 wideband on every call leg where both endpoints support it — internal calls, supported carrier interconnects, and conferencing — falling back to G.711 only at unavoidable PSTN gateways, so end users hear HD Voice by default rather than as a premium add-on.