[sane-devel] [janitorial] New backend: escl

Till Kamppeter till.kamppeter at gmail.com
Sun Dec 15 15:37:23 GMT 2019

On 15/12/2019 10:38, Till Kamppeter wrote:
> On 15/12/2019 05:10, Olaf Meeuwissen wrote:
>> Hi list,
>> I thought you might like to know that I've merged the escl backend
>> yesterday.  This backend was written by Touboul Nathane and Thierry
>> Huchard at Ordissimo.  It is licensed under the terms of the GPL,
>> either version 3 or, at your option, any later version.
>> The backend should support many of the large range of devices that
>> support Apple's AirPrint protocol.  For a long list of potentially
>> supported devices see
>>    https://support.apple.com/en-us/HT201311
>> The backend's description file does not list any specific devices yet
>> but the merge request listed a few devices that are known to work for
>> some definition of work ;-)
>> Please note that the escl backend only supports these devices over a
>> network connection, not via USB or similar connections.
>> The backend currently only supports image data transfer in JPEG format
>> but Thierry indicated he wanted to add support for PNG and PDF as well.
>> For the gory details see merge request 242.
>>    https://gitlab.com/sane-project/backends/merge_requests/242
>> On a related note, there is another merge request for a canon_lide70
>> backend.  I'll be getting to that shortly, relatively speaking :-)
>> Hope this helps,
> I have the HP DeskJet 2540 MF device here. Its DNS-SD record is:
> ----------
> Found service 'Deskjet 2540 series [E7DDC7]' of type '_uscan._tcp' in domain 
> 'local' on 3.1.
> Service data for service 'Deskjet 2540 series [E7DDC7]' of type '_uscan._tcp' in 
> domain 'local' on 3.0:
>      Host HP5CB901E7DDC7.local (, port 8080, TXT data: 
> ['duplex=F', 'is=platen', 'cs=binary,color,grayscale', 'rs=/eSCL', 
> 'representation=', 'UUID=1c852a4d-b800-1f08-abcd-5cb901e7ddc7', 'note=', 
> 'adminurl=http://HP5CB901E7DDC7.local.', 'ty=HP Deskjet 2540 series', 
> 'pdl=application/octet-stream,application/pdf,image/jpeg', 'vers=2.0', 'txtvers=1']
> ----------
> Seems that it also supports eSCL, with JPEG and PDF as output format.
>     Till

Seeing that my HP does eSCL, I have investigated the source code of HPLIP, the 
free software HP printer/MF device driver suite, and it seems to also support 
eSCL for scanning, containing the source file


This could perhaps contain missing pieces for your eSCL backend, like PDF (or 
any uncompressed raster) output, USB support, ...

In the list of supported models


on all with "scan-type=9" sSCL is used by HPLIP (see also io/hpmud/hpmud.h), but 
there are more models, like ny DeskJet 2540 which supports eSCL according to its 
DNS-SD record.



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