Note: [2002-06-20] There seems to be a bug in the ST400 driver or maybe even the scanner firmware (probably only showing up with Linux Kernel 2.4.x). If you get distorted images, try setting "maxread" in st400.conf to 32768.

The Siemens "HighScan" ST400 is an ancient 1-pass SCSI flatbed scanner, supporting B&W and grayscale (6bit) in 200, 300 and 400 DPI. It is hardwired to SCSI ID 3 and answers to all 8 LUNs. In /proc/scsi/scsi on Linux, my scanner shows up as:

    Host: scsi1 Channel: 00 Id: 03 Lun: 00
      Vendor: SIEMENS  Model: ST 400           Rev: GS04
      Type:   Scanner                          ANSI SCSI revision: 02

Although the inquiry data says SCSI-2, this scanner is in fact pre-SCSI-2 and uses slightly different SCSI command parameters - for example, the scan window dimensions are specified with 16bit-values instead of 32bit. Unfortunately, I have no documenation for this scanner (some time ago, I sent an email to Siemens asking for docs, but received no answer so far). All my programming information is from an old Amiga program (an updated version of this program can be found on the download section below) and a lot of try-and-error. Therefore this backend is about as minimal as a SANE driver can be.

The available options are (pasted output from scanimage -h):

    --resolution 200|300|400dpi [200]
        Sets the resolution of the scanned image.
    --depth 1|8bit [1]
        Number of bits per sample, typical values are 1 for "line-art" and 8
        for multibit scans.
    --threshold 0..100% [50]
        Select minimum-brightness to get a white point
  Geometry:
    -l 0..215.9mm [0]
        Top-left x position of scan area.
    -t 0..304.8mm [0]
        Top-left y position of scan area.
    -x 0..215.9mm [0]
        Width of scan-area.
    -y 0..304.8mm [0]
        Height of scan-area.

The --threshold option is only valid for a bit depth of 1. Instead of 6bit-values, the backend gives 8bit, as required by the SANE standard.

Version 1.6 was included in SANE 1.0.3, so newer versions are now automatically included in the default distribution, you don't need patches from this site.

• Version 1.3 as a patchfile for SANE 1.0.1. Download it, go into SANE's toplevel directory, and do

  gunzip < st400-1.3-for-1.0.1-patch.gz | patch -p1

  Then re-run configure and make.

• Version 1.4 as a similar patchfile (do not apply this patch on top of the previous one, but on an unpatched SANE 1.0.1). This version has lots of config options for testing different scanner models (see st400.conf for details).
• Version 1.5 as a similar patchfile for SANE 1.0.2, or as a tarball of files (as drop-in-replacements, if you already applied one of the other patches). This version guards against lock-ups with large buffers as used by default in SANE 1.0.2 and the new Linux sg driver (the scanner doesn't like transfer requests for more than 64KB of data).
• Version 1.6 (similar patch, or set of files). Fixes some minor type mismatches in debug messages.

• A Windows 3.x scanning program (300KB, binary only) is available from Siemens - use the search facility ("Volltextsuche") to search for 'HIGHSCAN'. I could not get it to work on a 486DX/2-66 runing Win 3.11 - the program immediately claims to run out of memory even though the machine is equipped with 48MB. This might be due to a misconfigured system - I'm a Unix guy, and don't know much about Windows.
• An Amiga program is available on Aminet (100KB, binary & source, GNU GPL). See this README file for more information.

Any questions? Just send mail: Ingo.Wilken@informatik.uni-oldenburg.de