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mod_dptools: queue_dtmf

Table of Contents (click to expand)

0. About

Send DTMF digits after a bridge is successful from the session using the method(s) configured on the endpoint in use.

1. Usage

queue_dtmf <dtmf digits>[@<tone_duration>]


  • the character w (lower-case w) for a half second delay, and
  • the character W (upper-case w) for a 1 second delay.

2. Examples

<action application="queue_dtmf" data="0123456789ABCD*#@100"/>
<action application="bridge" data="sofia/internal/101"/>

Transmit the digits 0123456789ABCD*#, each having a duration of 100ms after connecting to extension 101. If no duration is specified the default DTMF length of 2000ms will be used.

2.1 Using execute_on_answer

Some have reported lack of success using queue_dtmf with some TDM cards. User Wayne reports that this worked for him with a Sangoma card:

<extension name="test-tone" >
<condition field="destination_number" expression="1(.*)" >
<action application="set" data="effective_caller_id_number=9025556747"/>
<action application="sleep" data="500"/>
<action application="flush_dtmf"/>
<action application="export" data="nolocal:execute_on_answer=send_dtmf W$1#@500" />
<action application="bridge" data="freetdm/wp1/a/18005551234"/>

3. Options

For SIP calls, the digits can be transmitted via inband, RFC2833, or INFO messages.

See Sofia_Configuration_Files for configuration of DTMF transmission methods in mod_sofia.

TODO RFC 2833 is obsoleted by RFC 4733.