NAME

       sane-rts8891 - SANE backend for rts8891 based scanners

DESCRIPTION

       The  sane-rts8891  library  implements  a  SANE (Scanner Access Now Easy) backend that provides access to
       scanners based on the rts8891 ASIC.

       The scanners that work with this backend are:

                 Vendor Model           status
              ----------------------  -----------
                Umax Astra 4400       untested
                Umax Astra 4450       untested
                HP scanjet 4000c      good
                HP scanjet 4470c      good

       The options the backend supports can either be selected through command line  options  to  programs  like
       scanimage(1) or through GUI elements in xscanimage(1) or xsane(1).

       If you notice any strange behavior, please report to the backend maintainer or to the SANE mailing list.

       Valid command line options and their syntax can be listed by using

              scanimage --help -d rts8891

       Scan Mode Options

       --mode selects  the  basic  mode  of operation of the scanner. Valid choices are Color, Gray and Lineart.
              The default mode is Color.  The Lineart mode is for black and  white  only  (1  bit).   Gray  will
              produce  256  levels  of  gray  (8  bits).  Color mode allows for over 16 million different colors
              produced from 24 bits of color information.

       --resolution
              selects the resolution for a scan. The horizontal and vertical resolutions are set by the value of
              this option. The scanner is capable of the following resolutions for the specified option value:

                Value   Hor. Resolution  Vert. Resolution
                -----   ---------------  -------------------
                75      75dpi            75dpi
                150     150dpi           150dpi
                300     300dpi           300dpi
                600     600dpi           600dpi
                1200    1200dpi          1200dpi

       --preview
              requests a preview scan. The resolution used for that scan is 75 dpi and the  scan  area  and  the
              scan  mode  are  as  specified through their options, or the default if not specified. The default
              value for preview mode is "no".

       --threshold
              selects the  minimum-brightness to get a white point. The threshold is only used with Lineart mode
              scans.  It is specified as a percentage in the range 0..100% (in steps of 1).  The  default  value
              of the threshold option is 50.

CONFIGURATION FILE

       The configuration file /etc/sane.d/rts8891.conf contains the usb device ids of supported scanners (eg usb
       0x043d  0x007c)  and  scanner configuration options.  Empty lines and lines starting with a hash mark (#)
       are ignored.

       The options supported are allowsharing, modelnumber

       Option

       allowsharing
              enables or not the sharing of the scanner between multiple frontends at the same time.

       modelnumber
              is used to force the reported model by the backend and is only useful in the  case  of  a  scanner
              which NVRAM has been erased.

              0 to report a HP4470c.
              1 to report a HP4400c.
              2 to report an Astra 4400.

FILES

       /usr/lib/x86_64-linux-gnu/sane/libsane-rts8891.a
              The static library implementing this backend.

       /usr/lib/x86_64-linux-gnu/sane/libsane-rts8891.so
              The shared library implementing this backend (present on systems that support dynamic loading).

ENVIRONMENT

       SANE_DEBUG_RTS8891 SANE_DEBUG_RTS8891_LOW SANE_DEBUG_RTS88XX_LIB
              If  the  library  was compiled with debug support enabled, these environment variables control the
              debug level for this backend. E.g., a value of 255  requests  all  debug  output  to  be  printed.
              Smaller levels reduce verbosity.

LIMITATIONS

       Scanners  of  the same model exist with different sensors, due to lack of data (ie USB logs) some sensors
       are better supported than others. At least 75 dpi mode is working for  any  model.  Sharing  the  scanner
       between several frontends at the same time (allowsharing option) may not work on some USB controllers.

       XPA is not (yet) supported.

BUGS

       No bugs currently known.

SEE ALSO

       sane-scsi(5), scanimage(1), xscanimage(1), xsane(1), sane(7)

AUTHOR

       This backend has been developed by Stéphane Voltz.
              http://stef.dev.free.fr/sane/rts8891

CREDITS

       Many thanks go to:
              Laurent  Fournier  who  donated me a HP4470c.  Vladimir Sysoev and "TheUnruly Squash" for the time
              they spent recording USB activity and testing the experimental version on HP4400 models.

                                                   8 Dec 2008                                    sane-rts8891(5)