Mine

  <!-- Example extension for require auth per-call. -->
  <extension name="us_national">
    <!-- Match the destination digits of 1NxxNxxxxxx -->
    <condition field="destination_number" expression="^1?([2-9]\d\d[2-9]\d{6})$"/>
    <!-- Make sure the sip_authorized variable is set (set on all authed calls)
         If it isn't, then send an auth challange.
    -->
    <condition field="${sip_authorized}" expression="true">
      <anti-action application="reject" data="407"/>
    </condition>

    <!-- If you made it here all is well and the call is authed.
         Do whatever you wish.
    -->
    <condition>
      <action application="info"/>
      <action application="bridge" data="sofia/$${sip_profile}/1$1@207.210.228.173"/>
    </condition>
  </extension>