[Printers] DocuColor column 15

[Seth David Schoen]

The interpretation by Joel and Patrick that column 15 represents the
first two decimal digits of the serial number makes sense for many
printers with leading zeroes, but it turns out that several samples
we have show values of column 15 greater than 100.

For example, we have a DocuColor 6060 with column 15 equal to
2+4+16+32+64=118.  This is not a rare anomaly, but turns out to be
typical of several of our DocuColor samples.

I don't think column 15 can be part of the serial number, or at least
not a binary-coded-decimal part of the serial number.  One possibility
is that it may identify the model or particular options set on the
printer.  Complicating this is the fact that several of our DocuColor 12
samples have columns 14 and 15 set to zero (and appear also to have
serial numbers with many leading zeroes).

Although I've seen many samples with the column 15 value greater than
100, I haven't seen any with column 14 greater than 100.  So the
interpretation of column 14 as part of the serial number still makes
sense.

The value of column 15 appears to be constant over time for any given
printer.  I have sheets printed on particular DocuColor printers in June
and sheets printed on the same printers in September, and the column 15
values seem to match up.  So it is something unique to the printer, but
it's not clear whether it's literally part of the serial number or
whether it might reflect some kind of model number or configuration.

-- 
Seth Schoen
Staff Technologist                                schoen at eff.org
Electronic Frontier Foundation                    http://www.eff.org/
454 Shotwell Street, San Francisco, CA  94110     1 415 436 9333 x107