Source note · Troubleshooting fax over IP failures
RFC 6913 defines the sip.fax media feature tag with values t38 (fax will use ITU-T T.38) and passthrough (fax will be carried in G.711).
Checked 2026-10-02
- Vendor
- not restricted
- Product
- not restricted
- Subsystem
- SIP fax capability
- Deployment
- any
- Region
- not restricted
- Release range
- RFC 6913, March 2013
- Checked
- 2026-10-02
Sources
- Indicating Fax over IP Capability in the Session Initiation Protocol (SIP) — IETF RFC Editor · tier 1 standards and regulators · Section 4
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting fax over IP failures: source note fax-over-ip-troubleshooting-rfc6913-tag-values. WarmTransfer. https://warmtransfer.net/knowledge/claims/fax-over-ip-troubleshooting-rfc6913-tag-values
BibTeX
@misc{warmtransfer-claim-fax-over-ip-troubleshooting-rfc6913-tag-values,
title = {Troubleshooting fax over IP failures: source note fax-over-ip-troubleshooting-rfc6913-tag-values},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/fax-over-ip-troubleshooting-rfc6913-tag-values},
note = {Source note fax-over-ip-troubleshooting-rfc6913-tag-values, checked 2026-10-02}
}