Because a user can have multiple endpoints, support of SIP 183 is not possible on inbound bypassed calls and Direct Routing always uses 180 Ringing in that case.

Checked 2026-09-16

Given that a user can have multiple endpoints, support of 183 is not possible. The Direct Routing will always use 180 Ringing in this case.
Vendor
Microsoft
Product
Teams Phone Direct Routing
Subsystem
Local Media Optimization signalling
Deployment
multi-tenant
Region
not restricted
Release range
current as of 2026-09-16
Checked
2026-09-16

Sources

Cite this note

APA

WarmTransfer. (2026, September 16). CUCM to Teams Phone migration: source note cucm-to-teams-phone-lmo-180-ringing. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-to-teams-phone-lmo-180-ringing

BibTeX

@misc{warmtransfer-claim-cucm-to-teams-phone-lmo-180-ringing,
  title  = {CUCM to Teams Phone migration: source note cucm-to-teams-phone-lmo-180-ringing},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/cucm-to-teams-phone-lmo-180-ringing},
  note   = {Source note cucm-to-teams-phone-lmo-180-ringing, checked 2026-09-16}
}

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