Source note · DTMF methods and interoperability failures
When a PSTN leg delivers DTMF only as in-band audio, the Direct Routing SBC has to convert it to a non-in-band method before it reaches Teams, or Teams IVRs and voicemail will not see the digits.
inferred · Checked 2026-09-24
- Vendor
- Microsoft
- Product
- Teams Phone Direct Routing
- Subsystem
- SBC interworking
- Deployment
- multi-tenant
- Region
- not restricted
- Release range
- current as of 2026-09-24
- Status
- inferred
- Checked
- 2026-09-24
Sources
- Teams Phone Direct Routing: Definitions and RFC standards — Microsoft · tier 2 current vendor documentation · Section 'DTMF' combined with RFC 4733 Section 2.5.2.2
Cite this note
APA
WarmTransfer. (2026, September 24). DTMF methods and interoperability failures: source note dtmf-interop-teams-dr-sbc-must-convert-inband. WarmTransfer. https://warmtransfer.net/knowledge/claims/dtmf-interop-teams-dr-sbc-must-convert-inband
BibTeX
@misc{warmtransfer-claim-dtmf-interop-teams-dr-sbc-must-convert-inband,
title = {DTMF methods and interoperability failures: source note dtmf-interop-teams-dr-sbc-must-convert-inband},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/dtmf-interop-teams-dr-sbc-must-convert-inband},
note = {Source note dtmf-interop-teams-dr-sbc-must-convert-inband, checked 2026-09-24}
}