In scenarios where a Vendor sends a 183 Session Progress followed by a 180 Ringing message, some Caller UAs may fail to play a ringback tone to the user.
This feature is managed via a checkbox in Account Preferences and Account Class (note: Account Class settings apply only to newly created accounts). While ringback is typically the responsibility of the UA or Vendor, Sippy can generate it server-side if the Caller’s UA is misconfigured or outdated.
When Generate Ringbacktone is enabled, Sippy transmits ringing audio to the Caller during the provisioning stage upon receiving 183/180 messages from the Vendor. This continues until a 200 OK is received and processed.
Supported codec formats for the feature:
- g711u (0)
- g711a (8)
- g723 (4)
- g729 (18)
- GSM (3)
