Cutover plan

Write the gate that can stop the morning.
A Cisco, Avaya, or Asterisk gateway is a SIP story, not an importer.
Confirm the technical requirements PDF before cutover.

Sources and go deeper

Planning your implementation. vendor. last checked 2026-10.
Technical requirements PDF. vendor. last checked 2026-10.
IANA service names and port numbers. ports. last checked 2026-10.
RFC 3261, SIP: Session Initiation Protocol. rfc. last checked 2026-10.
Interactive voice response. wikipedia. last checked 2026-10.