G.722 carries wideband speech with audio bandwidth up to 7 kHz at a 64 kbit/s encoded rate. It can make compatible internal or IP-to-IP calls clearer, but a narrowband PSTN leg or incompatible endpoint will constrain or transcode the call.
Settings used in this guide
These are public service values, not your password or account-specific authentication ID.
| Approved codec order | Confirm in your UKDDI activation email |
|---|---|
| Media security | SRTP |
Why G.722 can sound clearer
Traditional telephone audio is narrowband. G.722 codes a wider speech spectrum, up to 7 kHz audio bandwidth, which can improve consonant clarity and reduce listening effort when the complete path stays wideband.
- Both endpoints must support and actually negotiate G.722.
- The PBX, SBC, recording, conference and carrier legs must pass it without narrowing the call.
- A call entering the traditional PSTN can become narrowband regardless of the office handset.
- The encoded 64 kbit/s rate still needs packet and network overhead added.
Good and poor use cases for G.722
Keep G.722 in the order only when it is enabled and useful for the route. The live UKDDI order is Confirm in your UKDDI activation email.
Calls between compatible office users, branches or supported SIP endpoints where the entire media path stays wideband.
External UKDDI/PSTN calls, call recording, contact-centre platforms, conferences and mobile networks where a narrowband leg may be introduced.
Configure G.722 without breaking PSTN calls
- 1Separate internal and carrier policies
It can be sensible to prefer G.722 on extension-to-extension calls while retaining the carrier-approved order on the UKDDI trunk.
- 2Check every application
Confirm voicemail, recording, IVR, music on hold and conference resources can pass or intentionally transcode G.722.
- 3Retain an approved fallback
Use G.711 A-law where supported for calls that cannot remain wideband; avoid an uncontrolled list of codecs.
- 4Measure PBX processing
If transcoding is unavoidable, monitor CPU/DSP capacity under the maximum concurrent call load.
Prove the call remains wideband
- 1Inspect SDP and call statistics
Verify G.722 was negotiated on each leg; an HD icon alone may describe only the handset side.
- 2Test representative routes
Compare internal, branch, UK landline, UK mobile, voicemail, recorded and conference calls.
- 3Listen and measure
Check subjective clarity alongside loss, jitter, latency and any transcoder resource alarms.
- 4Verify encryption
Confirm SRTP remains negotiated on every leg required by the security policy.