Old Fred, I can always be wrong, but the XX2247 is
the depth of cut for
the 6 slots of the key. X means no cut and 2247 are the depths for the 4
cuts on the key. Someone with an original key can confirm if there is a
sequence of two non-cuts, two equal cuts and two different cuts on the key?
The only problem with this theory is that there are 7 cuts in the key (and
7 pins in the lock) -- I've just looked at the XX2247 key that I use in my
8/e. So it must be a 'code' -- an index number to the codebook which
givethe 7 depths.
-tony