Dual-Tone Multi-Frequency Signaling; Configuring Dtmf Transport Types - AudioCodes Mediant 3000 User Manual

13.3.3 Dual-Tone Multi-Frequency Signaling

This section describes the configuration of Dual-Tone Multi-Frequency (DTMF) signaling.

13.3.3.1 Configuring DTMF Transport Types

The device supports various methods for transporting DTMF digits over the IP network to
the remote endpoint. These methods and their configuration are configured in the DTMF &
Dialing page (Configuration tab > VoIP menu > GW and IP to IP > DTMF and
Supplementary > DTMF & Dialing):

Using INFO message according to Nortel IETF draft: DTMF digits are sent to the
remote side in INFO messages. To enable this mode, define the following:
a. Set the 'Declare RFC 2833 in SDP' parameter to No (RxDTMFOption = 0).
b. Set the '1st Tx DTMF Option' parameter to INFO (Nortel) (TxDTMFOption = 1).
Note: In this mode, DTMF digits are removed from the audio stream (and the 'DTMF
Transport Type' parameter is automatically set to Mute DTMF).

Using INFO message according to Cisco's mode: DTMF digits are sent to the
remote side in INFO messages. To enable this mode, define the following:
a. Set the 'Declare RFC 2833 in SDP' parameter to No (RxDTMFOption = 0).
b. Set the '1st Tx DTMF Option' parameter to INFO (Cisco) (TxDTMFOption = 3).
Note: In this mode, DTMF digits are removed from the audio stream (and the 'DTMF
Transport Type' parameter is automatically set to Mute DTMF).

Using NOTIFY messages according to IETF Internet-Draft draft-mahy-sipping-
signaled-digits-01: DTMF digits are sent to the remote side using NOTIFY
messages. To enable this mode, define the following:
a. Set the 'Declare RFC 2833 in SDP' parameter to No (RxDTMFOption = 0).
b. Set the '1st Tx DTMF Option' parameter to NOTIFY (TxDTMFOption = 2).
Note: In this mode, DTMF digits are removed from the audio stream (and the 'DTMF
Transport Type' parameter is automatically set to Mute DTMF).

Using RFC 2833 relay with Payload type negotiation: DTMF digits are sent to the
remote side as part of the RTP stream according to RFC 2833. To enable this mode,
define the following:
a. Set the 'Declare RFC 2833 in SDP' parameter to Yes (RxDTMFOption = 3).
b. Set the '1st Tx DTMF Option' parameter to RFC 2833 (TxDTMFOption = 4).
Note: To set the RFC 2833 payload type with a value other than its default, use the
RFC2833PayloadType parameter. The device negotiates the RFC 2833 payload type
using local and remote SDP and sends packets using the payload type from the
received SDP. The device expects to receive RFC 2833 packets with the same
payload type as configured by this parameter. If the remote side doesn't include
'telephony-event' in its SDP, the device sends DTMF digits in transparent mode (as
part of the voice stream).

Sending DTMF digits (in RTP packets) as part of the audio stream (DTMF Relay
is disabled): This method is typically used with G.711 coders. With other low-bit rate
(LBR) coders, the quality of the DTMF digits is reduced. To enable this mode, define
the following:
a. Set the 'Declare RFC 2833 in SDP' parameter to No (RxDTMFOption = 0).
b. Set the '1st Tx DTMF Option' parameter to Not Supported (TxDTMFOption = 0).
c. Set the ini file parameter, DTMFTransportType to 2 (i.e., transparent).

Using INFO message according to Korea mode: DTMF digits are sent to the
remote side in INFO messages. To enable this mode, define the following:
a. Set the 'Declare RFC 2833 in SDP' parameter to No (RxDTMFOption = 0).
User's Manual 184
Mediant 3000
Document #: LTRT-89729