I am a new in Freeswitch..

I need a help with start_dtmf parameter

We have IVR system (Telephone Reporting System)

Some times in incoming calls Freeswitch misses some key presses (DTMF)

I guess that the problem is the detection of DTMF...

I use in (external.xml)

<param name="dtmf-type" value="rfc2833"/>

Where I need to add start_dtmf parameter for detecting in-band DTMF ?

We are using  dialplan.xml file located in root of conf folder

<?xml version="1.0" encoding="utf-8"?>

<include>

  <context name="public">

  <extension name="SYFreeSwitch">

  <condition field="destination_number" expression=".*">

<action application="start_dtmf" />

  <action application="managed" data="SYFreeSwitch"/>

  </condition>

  </extension>

  </context>

</include>

It's right place for it ?

Thank you in advance,

Yigal