@b12b & Neil your both correct, Been reading this tutorial & post # 32 in the link :
Spoiler:
http://www.gpspower.net/garmin-tutorials/298060-city-navigators-nt-unicode-ntu-compatible-devices-list-4.html#post983889

Then checking my garmindevice.xml file i found this :

<DataType><Name>UnicodeMaps</Name><File><Specification><Identifier>IMG</Identifier>
</Specification><Location><Path>Map</Path><FileExtension>img</FileExtension></Location>
<TransferDirection>InputOutput</TransferDirection></File></DataType>


Off into the NTU Section