Source note · Moving from Unified CM to Zoom Phone
Zoom's BYOC-P/BYOP-P call processing article states that on outbound calls from Zoom, Zoom supports PRACK for reliable 1xx responses but does not use REFER or SUBSCRIBE/NOTIFY.
disputed · Checked 2026-09-25
Zoom supports the PRACK mechanism for reliable 1XX responses but does not use REFER or SUBSCRIBE/NOTIFY.
- Vendor
- Zoom
- Product
- Zoom Phone
- Subsystem
- SIP call processing
- Deployment
- multi-tenant
- Region
- not restricted
- Release range
- current as of 2026-09-25
- Status
- disputed
- Checked
- 2026-09-25
Sources
- BYOC-P or BYOP-P call processing — Zoom Communications · tier 2 current vendor documentation · Outbound calls from Zoom section
Cite this note
APA
WarmTransfer. (2026, September 25). Moving from Unified CM to Zoom Phone: source note cucm-to-zoom-phone-refer-not-used. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-to-zoom-phone-refer-not-used
BibTeX
@misc{warmtransfer-claim-cucm-to-zoom-phone-refer-not-used,
title = {Moving from Unified CM to Zoom Phone: source note cucm-to-zoom-phone-refer-not-used},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cucm-to-zoom-phone-refer-not-used},
note = {Source note cucm-to-zoom-phone-refer-not-used, checked 2026-09-25}
}