freeswitch/conf/dialplan/public.xml

<!-- http://wiki.freeswitch.org/wiki/Dialplan_XML -->
<include>
  <context name="public">

    <extension name="loop">
      <condition field="${sip_looped_call}" expression="^true$">
	<action application="transfer" data="${destination_number} XML default"/>
      </condition>
    </extension>

    <extension name="public_extensions">
      <condition field="destination_number" expression="^(10[01][0-9])$">
	<action application="transfer" data="$1 XML default"/>
      </condition>
    </extension>

    <extension name="public_did">
      <condition field="destination_number" expression="^(5551212)$">
	<action application="transfer" data="$1 XML default"/>
      </condition>
    </extension>

  </context>
</include>