This will become something in the future, but for now.
JD..: reserved for JD use
JDCX: JD control sequences
Allowed characters: anything unambiguous in either case.
acdefghjkmnprtuvwxyz2345679
Case-insensitive.
B/8.
l/1.
0/O.
Q/0.
I/i/1.
S/5.
In other words, what Cisco would have done to their serial numbers if they hadn't been cretins.