In default

<extension name="incoming did">
  <condition field="destination_number" expression="^PHONE_NUMBER$">
    <action application="transfer" data="PHONE_NUMBER XML ictcore"/>
  </condition>
</extension>

In fax receiving context

<extension name="incoming did">
  <condition field="destination_number" expression="^PHONE_NUMBER$">
    <action application="rxfax" data="necessary options"/>
  </condition>
</extension>