Source note · DTMF methods and interoperability failures
If no 'events' fmtp parameter is received, an RFC 4733 sender SHOULD assume the peer supports DTMF events 0-15 and no other events.
Checked 2026-09-24
For backward compatibility, if no "events" parameter is received, the sender SHOULD assume support for the DTMF events 0-15 but for no other events.
- Vendor
- IETF
- Product
- RTP telephone-event payload
- Subsystem
- SDP negotiation
- Deployment
- any
- Region
- not restricted
- Release range
- RFC 4733
- Checked
- 2026-09-24
Sources
- RFC 4733: RTP Payload for DTMF Digits, Telephony Tones, and Telephony Signals — IETF / RFC Editor · tier 1 standards and regulators · Section 2.5.1.1 Negotiation of Payloads
Cite this note
APA
WarmTransfer. (2026, September 24). DTMF methods and interoperability failures: source note dtmf-interop-events-param-default. WarmTransfer. https://warmtransfer.net/knowledge/claims/dtmf-interop-events-param-default
BibTeX
@misc{warmtransfer-claim-dtmf-interop-events-param-default,
title = {DTMF methods and interoperability failures: source note dtmf-interop-events-param-default},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/dtmf-interop-events-param-default},
note = {Source note dtmf-interop-events-param-default, checked 2026-09-24}
}