FreeSWITCH

Add this near the end of your default dialplan:

<extension name="SpacePhone ENUM">
    <condition>
        <action application="set" data="continue_on_fail=true"/>
        <action application="set" data="hangup_after_bridge=true"/>
        <action application="enum" data="31979$1 e164.spacephone.org"/>
        <action application="bridge" data="${enum_auto_route}"/>
        <action application="playback" data="tone_stream://%(330,15,950);%(330,15,1400);%(330,1000,1800);loops=2"/>
        <action application="playback" data="ivr/ivr-unallocated_number.wav"/>
        <action application="playback" data="tone_stream://%(330,15,950);%(330,15,1400);%(330,1000,1800);loops=2"/>
    </condition>
</extension>

To narrow its scope (and make sure not every number hits this extension), use this snippet:

<extension name="SpacePhone ENUM">
    <condition regex="any">
        <regex field="destination_number" expression="^(11010000\d\d\d)$"/><!-- US +1  101 0000 xxx -->
        <regex field="destination_number" expression="^(319799\d\d)$"/>    <!-- NL +31 979  9xx   -->
        <regex field="destination_number" expression="^(329919\d\d)$"/>    <!-- BE +32 99   19xx  -->
        <regex field="destination_number" expression="^(448990190\d\d)$"/> <!-- UK +44 8990 190xx -->
        <regex field="destination_number" expression="^(45379\d\d)$"/>     <!-- DA +45 19xx -->
        <regex field="destination_number" expression="^(49199119\d\d)$"/>  <!-- DE +49 199  119xx -->
        <action application="set" data="continue_on_fail=true"/>
        <action application="set" data="hangup_after_bridge=true"/>
        <action application="enum" data="31979$1 e164.spacephone.org"/>
        <action application="bridge" data="${enum_auto_route}"/>
        <action application="playback" data="tone_stream://%(330,15,950);%(330,15,1400);%(330,1000,1800);loops=2"/>
        <action application="playback" data="ivr/ivr-unallocated_number.wav"/>
        <action application="playback" data="tone_stream://%(330,15,950);%(330,15,1400);%(330,1000,1800);loops=2"/>
    </condition>
</extension>