freeswitch/conf/insideout/directory/default/default.xml

<include>
  <user id="default"> <!--if id is numeric mailbox param is not necessary-->
    <variables>
      <!--all variables here will be set on all inbound calls that originate from this user -->
      <!-- set these to take advantage of a dialplan localized to this user -->
      <variable name="numbering_plan" value="$${default_country}"/>
      <variable name="default_areacode" value="$${default_areacode}"/>
      <variable name="default_gateway" value="$${default_provider}"/>
    </variables>
  </user>
</include>