rfc-4458
Session Initiation Protocol (SIP) URIs for Applications such as Voicemail and Interactive Voice Response (IVR)
The Session Initiation Protocol (SIP) is often used to initiate connections to applications such as voicemail or interactive voice recognition systems. This specification describes a convention for forming SIP service URIs that request particular services based on redirecting targets from such applications. This memo provides information for the Internet community.
updated by
- rfc-8119 — SIP "cause" URI Parameter for Service Number Translation