Source note · DTMF methods and interoperability failures
The first RTP packet for a telephone event MUST have the marker (M) bit set.
Checked 2026-09-24
The first packet for an event MUST have the M bit set.
- Vendor
- IETF
- Product
- RTP telephone-event payload
- Subsystem
- sender behaviour
- 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 2.5.1.2 Transmission of Event Packets
Cite this note
APA
WarmTransfer. (2026, September 24). DTMF methods and interoperability failures: source note dtmf-interop-first-packet-m-bit. WarmTransfer. https://warmtransfer.net/knowledge/claims/dtmf-interop-first-packet-m-bit
BibTeX
@misc{warmtransfer-claim-dtmf-interop-first-packet-m-bit,
title = {DTMF methods and interoperability failures: source note dtmf-interop-first-packet-m-bit},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/dtmf-interop-first-packet-m-bit},
note = {Source note dtmf-interop-first-packet-m-bit, checked 2026-09-24}
}