Name: Yealink SIP-T48G
Brand: Yealink
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Administrator’s Guide for SIP-T2 Series/T19(P) E2/T4 Series/CP860 IP Phones

384

 SIP INFO -- DTMF digits are transmitted by SIP INFO messages.

The method of transmitting DTMF digits is configurable on a per-line basis.

RFC 2833

DTMF digits are transmitted using the RTP Event packets that are sent along with the

voice path. These packets use RFC 2833 format and must have a payload type that

matches what the other end is listening for. The payload type for RTP Event packets is

configurable. IP phones default to 101 for the payload type, which use the definition to

negotiate with the other end during call establishment.

The RTP Event packet contains 4 bytes. The 4 bytes are distributed over several fields

denoted as Event, End bit, R-bit, Volume and Duration. If the End bit is set to 1, the

packet contains the end of the DTMF event. You can configure the sending times of the

end RTP Event packet.

INBAND

DTMF digits are transmitted within the audio of the IP phone conversation. It uses the

same codec as your voice and is audible to conversation partners.

SIP INFO

DTMF digits are transmitted by the SIP INFO messages when the voice stream is

established after a successful SIP 200 OK-ACK message sequence. The SIP INFO

message is sent along the signaling path of the call. The SIP INFO message can transmit

DTMF digits in three ways: DTMF, DTMF-Relay and Telephone-Event.

Procedure

Configuration changes can be performed using the configuration files or locally.

Configuration File

<MAC>.cfg

Configure the method of

transmitting DTMF digit and the

payload type.

Parameters:

account.X.dtmf.type

account.X.dtmf.dtmf_payload

account.X.dtmf.info_type

<y0000000000xx>.cfg

Configure the number of times

for the IP phone to send the end

RTP Event packet.

Parameter:

features.dtmf.repetition

Configure the duration time for

Yealink SIP-T48G Specifications

General