Source note · Troubleshooting fax over IP failures
Unlike audio, fax protocols cannot be transcoded, so a T.38 leg cannot be converted to a G.711 pass-through leg mid-path by a Cisco device.
Checked 2026-10-02
Fax protocols, unlike audio calls, cannot be transcoded.
- Vendor
- Cisco
- Product
- Cisco IOS voice gateways
- Subsystem
- call flow design
- Deployment
- on-premises
- Region
- not restricted
- Release range
- current as of 2026-10-02
- Checked
- 2026-10-02
Sources
- Commonly Supported Fax/Modem Call Flows — Cisco Systems · tier 2 current vendor documentation · Introduction / background on fax call flows
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting fax over IP failures: source note fax-over-ip-troubleshooting-fax-not-transcodable. WarmTransfer. https://warmtransfer.net/knowledge/claims/fax-over-ip-troubleshooting-fax-not-transcodable
BibTeX
@misc{warmtransfer-claim-fax-over-ip-troubleshooting-fax-not-transcodable,
title = {Troubleshooting fax over IP failures: source note fax-over-ip-troubleshooting-fax-not-transcodable},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/fax-over-ip-troubleshooting-fax-not-transcodable},
note = {Source note fax-over-ip-troubleshooting-fax-not-transcodable, checked 2026-10-02}
}