[sane-devel] Epson and epkowa

[Olaf Meeuwissen]

Hi,

I forgot to mention that we don't have documentation on either of the
two protocols that wrap the ESC/I and ESC/I-2 protocols for network
communication.

Olaf Meeuwissen writes:

> Hi Ralph,
>
> Ralph Little writes:
>
>> Hi,
>>
>> On 2020-05-18 4:48 a.m., Olaf Meeuwissen wrote:
>>>
>>>>>>> If so, what is the likelihood that epson2 would work with this
>>>>>>> scanner with moderate modifications?
>>> None.  The non-free interpreter is dlopen()ed by the epkowa backend and
>>> it converts the regular ESC/I protocol to the device's native protocol,
>>> insofar possible.  Mind you, there are *several* such native protocols.
>>> These native protocol are not even remotely close to the ESC/I protocol.
>>> You'd be better of trying to find a backend that uses something close.
>>> For a few of the interpreter using devices, the snapscan backend is a
>>> good match.  For others, I don't know.  Maybe sane-find-scanner can be
>>> of help to check whether it's something genesys-like, I don't know.
>>>
>>> While porting those interpreters at part of my work duties, I have
>>> tended not to look at the closed source more than absolutely needed to
>>> get them to compile and "work".  That was about a decade (or more) ago
>>> so I don't have any recollection anyway beyond what found its way into
>>> epkowa.desc :-P
>>>
>> Do we have any documentation regarding the ESC/I protocol?
>
> Yes.  Lots.
>
> At one point EPSON provided the protocol specs for a number of their
> scanners for download to developers.  The download terms were such that
> these documents cannot be made available to other folks but I have a
> bunch of dead-tree versions.
>
> I used those to implement something called [FreeRISCI][1] and added API
> documentation to it based on the implementation to work around the "NDA"
> for the documents.  I contacted EPSON at the time to check it that would
> be okay.  I don't remember the exact reply but it was something like "it
> is not not okay".
>
> The [Utushi][2] code actually incorporated much of the FreeRISCI code to
> add ESC/I support so you can find the documentation there as well.
>
>  [1]: https://launchpad.net/freerisci
>  [2]: https://gitlab.com/utsushi/utsushi
>
> There should be `doc` or `doxygen` `make` targets that produce HTML if
> you wish but it's all there in the C++ source code.  Actually, the
> Utsushi code also documents a fair deal of the ESC/I-2 protocol IIRC.
>
> Hope this helps,


--
Olaf Meeuwissen, LPIC-2            FSF Associate Member since 2004-01-27
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