[Printers] Re: scanned images

[bunnie]

Patrick,

thanks for the info. I gather you found the serial number for the
printer that you were looking for on my website earlier?

As for the times, I would not be surprised if the time was set
incorrectly on these machines. Do you happen to know how I can
look up the current time on the machine? I didn't see a configuration
option that was unlocked at the front panel that I could use to discover
the current time setting in the copier. These Doc12's are just in a
Fedex kinko's about five minutes from my house and it's a 24/7 shop
so it's pretty easy to get access to them.

>Regarding the HP 2600N info, the embedded data is in a different format.  I'm
>working on a promising method to extract the information embedded in the 
>image.
>  It appears there are only 8 bytes of data, and the first 4 bytes are the 
> same
>between the two 2600N printers.  Here is the data I've extracted so far --
>please note the bit order, nibble order and/or byte order may be reversed:
>
>For HP 2600N, S/N CNBC55L0QJ, Formatter F9221M9:
>   0xF0, 0xA5, 0x9C, 0x80, 0x01, 0x67, 0x10, 0xB7
>
>For HP 2600N, S/N CNBC573058, Formatter F921F6L:
>   0xF0, 0xA5, 0x9C, 0x80, 0x83, 0xC2, 0x50, 0xF8
>
>This data agrees with additional bitwise checksum data that is also embedded,
>which shows the 1s and 0s have been transcribed correctly.

Can you please tell me more about these additional bitwise checksums?
I'd like to understand more about the watermark and the methods you are
using to extract the data. I'm trying to figure out how to bypass
the watermarks in hardware and this could provide some clues to
the process.

Based on DC and mines' observation so far, we think that the 2600N does
not print a timestamp. We have looked at multiple printouts from the
same printer and the pattern is the same. Or rather, I don't see how this
one could print a timestamp--yet. I have yet to plug it into a network port
or a computer; I have only powered it on to print demo pages (this is a clean
box that I got for RE work, also a good excuse to get a color printer for 
future
use--that hopefully won't be watermarked once I'm done with it). Thus,
without an external time source, and with no visible backup battery
or RTC assembly (usually distinguishable by the 32.768 kHz can oscillator),
I can't imagine that the 2600N is doing any kind of useful timestamping.
It might be interesting to see if after I give it ethernet if it tries
to do some kind of NTP automatically....

thanks for the help! Any further hints and tips are appreciated!

-b.



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