You may have come across a few really sweet V 1.0 codes before, but you have Animal crossing V 1.1...but no more. I will explain to you how to change the version of codes.
Codes use a very specific language called "Hexidecimal Codes" which you may be farmilliar with if you have ever seen a scientific calculator. (most Windows users have a calculator with scientific mode under Accesories.) They contain the numbers 0-9 and the letters A-F. Here is a basic guide, D is decimal (the number system you are used to) H is hexidecimal (the new number system I'm introducing you to)
In the first "half" of the code, the V 1.1 code is 580 higher than the V. 1.0 code. The second half remains the same. This is true for ANY code that doesn't have an activation code. (Please note, to the extent of my knowledge, Wi-Fi codes can't be ported). Add 580 to the first half of any code that doesn't have an activation command (Ex. press L + up to activate) or isn't Wi-Fi compatable.