[Printers] Docu12 decoding guide & more

[Joel]

Hallo all,

What a great way to spend time not doing what i should be! :-)

Bellow I have gathered the info which i worked out today. First there are
a few transcriptions of the bit matrices for the Doc12 scans from bunnie's
blog as well as the two B3 pages (which have the same matrix by the way).
Just thought i'd add that stuff in to spare anyone else the hassle of
trying to read them off the .tiff files themselves.

Further i've given (my interpretation of) the encoding scheme for the
Xerox Doc12's. I have the same result as Patrick so basicaly this is just
a confirmation of what he read out of the watermarks along with the
details of how they are encoded. I thought it would be good to add that in
because maybe there are similarities between other watermarking schemes
(of other Xerox models or even other brands) so knowing the Doc12 scheme
might save sometime when decoding other watermarks.

Without more info on the serial & date/time as well as a few different
examples decoding the B3 watermark is really a guessing game (for me).
maybe someone else has more luck.

I als had a look at the german site which seth mention and wrote up a bit
about what i found there.

	--------------
	|Doc 12 Xerox|
	--------------


serial: 0000059046  @ real time 19:00  (03/09/05)
11.50.3H 1500345
encoded time: 10:35 (04/09/05)
-----------------------------------------
..111.111111111
...........1...
11........1....
...........1...
1...1.1...11...
1....1.1..1.1..
11..1.....11...
11....11....1..


serial: 0000059046  @ real time 19:01 (03/09/05)
encoded time: 10:36 (04/09/05)
----------------------------------------
11111.111111111
...........1...
11........1....
...........1...
1...1.1...11...
.1...1.1..1.1..
....1.....11...
......11....1..


serial: 0000059987  @ real time 18:50 (03/09/05)
11.50.3H menu1: 457686  menu2: 13339  menu3: 390031  menu4: 471045
encoded time: 08:20 (04/09/05)
----------------------------------------
1111..1111.1111
1.........11...
...........1...
11........1....
1...1.1........
.1...1.1..1.1..
1.........11...
......11..111..


serial: 0000059987  @ real time 18:51 (03/09/05)
encoded time: 08:22 (04/09/05)
----------------------------------------
..11..1111.1111
1.........11...
...........1...
11........1....
1...1.1........
.1...1.1..1.1..

.1........11...
......11..111..


serial: 0000059987  @ real time 18:53 (03/09/05)
encoded time: 08:24 (04/09/05)
----------------------------------------
1111..1111.1111
1.........11...
...........1...
11........1....
.1..1.1........
1....1.1..1.1..
1.........11...
......11..111..


serial: 0000059987  @ real time 18:54 (03/09/05)
encoded time: 08:25 (04/09/05)
----------------------------------------
..11..1111.1111
1.........11...
...........1...
11........1....
.1..1.1........
1....1.1..1.1..
1.........11...
11....11..111..


	--------------------
	|Encoding of Docu12|
	--------------------

Form: 8x15 bit matrix
Odd party: Row 1 and Col 1 are parity bits (only row 1 has even parity)
Unused: Columns 3,4,9,10
Date & Time:
	1) example date & time hh:mm DD/MM/YY = 10:36 04/09/05
	2) columns 2,5-8 encodes date time
	   column  |  pair  |  example  | example in binary
           ------------------------------------------------
              2    |   mm   |    36     |      0100100
	      5    |   hh   |    10     |      0001010
	      6    |   DD   |    4      |      0000100
	      7    |   MM   |    9      |      0001001
	      8    |   YY   |    5      |      0000101
Serial number:
	1) example serial of form abcdefghij = 0000059987
	2) seperate into pairs ab cd ef gh ij
	3) colums 11<->15 enocde a pair of numbers
	   column  |  pair  |  example  | example in binary
           ------------------------------------------------
              11   |   ij   |    87     |      1010111
	      12   |   gh   |    99     |      1100011
	      13   |   ef   |    05     |      0000101
	      14   |   cd   |    00     |      0000000
	      15   |   ab   |    00     |      0000000


Question @ patrick: Did you see anything different?
Question @ all    : Any idea why they waisted so much data? 4 extra
columns? inefficient representation?

--------------------------------------------------------------------------------
About that german site which seth commented on:
http://www.druckerchannel.de/ranking.php?tabelle=laser_farbe
is a list of all their colour-laser printer reviews. click on
"Testbericht" and then "Druckerqualitaet" or in one case on
"Gelddrucksperre".
Some printers i found on there site where the yellow dots where mentioned
are: HP 3700 series.
a search for "gelben punkten" = "yellow dots" comes up with the HP
laserjet 3500, 2500L and 4600n as well as the Minolta-QMS magicolor 2300DL
(& 2200DL)
in the Lanier LP124cx i also see a yellow dot on their sample image but
they dont mention it
--------------------------------------------------------------------------------


B3 pg.1
Format: 15x8 bit matrix
Odd Parity: Row 1 and Column 15 are parity bits (only row 15 has even
parity)
--------
1.1..1.. = 36
11.11.1. = 90
......1. = 2
1...1.1. = 10
11.1..11 = 83
.1111111 = 127
1....... = 0
1....... = 0
1....... = 0
1....... = 0
1....... = 0
1..1.1.. = 20
1....11. = 6
1....... = 0
1.11.111 < checksum
^
checksum

B3 pg.2  (same as pg.1)
--------
1.1..1..
11.11.1.
......1.
1...1.1.
11.1..11
.1111111
1.......
1.......
1.......
1.......
1..1.1..
1....11.
1.......
1.11.111


Thats all folks,
joel