I am extremely appreciative for the receipt of this map update. However I am somewhat confused as to what files are actually used for each type of GPS Unit. I have both a 3790 and a 1490 but I don't know which of the files that are uploaded to this site are actually to be used for example on my 1490T. For example, does my 1490T use ASR files or GS2 files? If so, can I upload them directly to my unit or to the Micro SD card? Is there perhaps some type of documentation saying what files are actually used for each unit? Perhaps an internal file detailing what files are actually used?