--- In gbadev@yahoogroups.com, Rob Kudla <yahoo-raindog469@k...>
wrote:
> On Thursday 02 October 2003 12:09, Ped wrote:
> > The e-reader itself can't have too much DPI IMHO, it has to
> > be cheap? Or not?
>
> I was thinking more along the lines of cheap inkjets not
> producing enough contrast at the edge of the dots.

The best I have had with trying to print, was a read error, meaning
some of the codes were scannable in the e-reader, and some of them
were not. If only we could eliminate the errors scanning produces
and that stuff, and have consistent contrast throughout the scan.

> I actually
> have no idea how 2-dimensional barcode scanners work (apart from
> the kind that acquires the whole image at once and analyses it
> in software, like that 2D-barcode-based "color fax" software
> someone was selling about 6 or 7 years ago.)

The e-reader is most definitely scan all at once type. The area
between the 4 big black dots are scanned in and decoded, then as you
move along, it scans the next area and decodes it. The reason for
the read error if you scan too fast, is that the optical scanner
flashes the light on and off, and if an area passes by the scanner
while the light is off, it will not be picked up.

> It also struck me that perhaps no one was able to get the cards
> to swipe because (a) the barcode is actually done in MICR
> (magnetic ink like the numbers at the bottom of checks) or (b)
> there's an embedded magstrip or RFID tag or something in the
> card. Of course, either of those situations would be pretty
> easy to discover if someone actually sacrificed an e-reader and
> dissected it, but I haven't seen anything like that on the web
> to date.

Nope, it is just a pure optical code. no magnetic ink or anything
like that.

> By the way, the creation of any program that encodes or decodes
> the barcodes will probably need to be done outside the US, due
> to the DMCA. The makers of that Cuecat barcode scanner claimed
> that their nearly standard barcode encoding was an effective
> access control mechanism, so Nintendo certainly could do so,
> especially if the resulting data stream has encryption that
> needs breaking.

Very much true. Also, not only would the encryption breaking have to
be done outside the US, the information would also have to be hosted
on a server outside the US as well.