Source note · Fax and T.38 in cloud calling
Cisco's ATA 191/192 guide says that when a Cisco media gateway terminates to the PSTN, T.38 fax relay should be disabled and fax enabled via modem passthrough (fax protocol pass-through g711ulaw with fax rate disable) with a T.38 alternative given.
Checked 2026-09-24
- Vendor
- Cisco
- Product
- ATA 191
- Subsystem
- gateway interworking
- Deployment
- on-premises
- Region
- not restricted
- Release range
- guide revision of 2026-01-30
- Checked
- 2026-09-24
Sources
- Cisco ATA 191 and ATA 192 Analog Telephone Adapter Administration Guide for Multiplatform Firmware - Advanced Options for Phone Services — Cisco · tier 2 current vendor documentation · Optimize Fax Completion Rates section; Cisco media gateway guidance
Cite this note
APA
WarmTransfer. (2026, September 24). Fax and T.38 in cloud calling: source note fax-t38-ata19x-cisco-gw-passthrough. WarmTransfer. https://warmtransfer.net/knowledge/claims/fax-t38-ata19x-cisco-gw-passthrough
BibTeX
@misc{warmtransfer-claim-fax-t38-ata19x-cisco-gw-passthrough,
title = {Fax and T.38 in cloud calling: source note fax-t38-ata19x-cisco-gw-passthrough},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/fax-t38-ata19x-cisco-gw-passthrough},
note = {Source note fax-t38-ata19x-cisco-gw-passthrough, checked 2026-09-24}
}