Source note · Troubleshooting fax over IP failures
When a fax relay call shows Failure To Train (FTT), Cisco advises checking T1/E1 digital interfaces for clocking errors and slips.
Checked 2026-10-02
- Vendor
- Cisco
- Product
- Cisco IOS voice gateways
- Subsystem
- TDM interface
- Deployment
- on-premises
- Region
- not restricted
- Release range
- current as of 2026-10-02
- Checked
- 2026-10-02
Sources
- Fax-SIP Troubleshoot Guide — Cisco Systems · tier 2 current vendor documentation · Troubleshoot section, TCF/FTT
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting fax over IP failures: source note fax-over-ip-troubleshooting-ftt-check-clocking. WarmTransfer. https://warmtransfer.net/knowledge/claims/fax-over-ip-troubleshooting-ftt-check-clocking
BibTeX
@misc{warmtransfer-claim-fax-over-ip-troubleshooting-ftt-check-clocking,
title = {Troubleshooting fax over IP failures: source note fax-over-ip-troubleshooting-ftt-check-clocking},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/fax-over-ip-troubleshooting-ftt-check-clocking},
note = {Source note fax-over-ip-troubleshooting-ftt-check-clocking, checked 2026-10-02}
}