Country Region code

Hi community, when you install AX 2012 R2, a list of country/region codes is also initialized.

You can find this via Organization administration > Setup > Addresses > Address setup (Fast tab Country Region. In this list a country code (which will be used in for example the customer's address) and the ISO code is available.

Question: does anybody know why the Country code (LogisticsAddressCountryRegion.CountryRegionId) is consisting 3 characters instead of the 2 characters of the ISO code? What is the purpose / idea behind this?

Thanks for replying.