!1 has already answered the question, but I thought it might use a bit of clarification. The thing that's being printed, ABCD, is the encoded form of that number. The fact that it shows up as ABCD can be considered as nothing more than a random coincidence (not that it necessarily is a random coincidence). The important part is that the bits are getting packed into a more compact representation, that just happens to show up as some letters when printed.