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HP Laserjet III via USB/LPT dongle to Windows XP?

Discussion in 'PC Hardware' started by Frantisek.Rysanek, Dec 2, 2008.

  1. Dear All,

    I've tried to attach an old HP LaserJet III to a modern notebook PC
    using a cheap USB-to-LPT dongle. I used the generic USB printing
    support (driver for the dongle) in XP, installed a HP LJ III printer
    manually (the stock XP driver) and pointed the printer profile to use
    the virtual USB printing port.

    The first result is, that it just doesn't work. The printing subsystem
    in Windows keeps trying something for a while, then merely says that
    the printing failed.

    I am aware that maybe the stock XP driver still relies on physical LPT
    hardware (or on LPT hardware-specific low-level driver in XP).

    There's also a slight chance of some hardware mismatch (logic levels
    mismatch, LPT/USB dongle under-powered, fuzzy PSU rails inside the
    dongle etc). The dongle is based on this chip (Prolific PL2305):
    http://www.prolific.com.tw/support/files/\IO Cable\PL-2305\Doc\Data Sheet\ds_pl2305_v1.3.pdf
    The USB device is clearly alive - the dongle is detected by the XP OS
    and the generic USB printing support driver gets loaded.

    Do you have any explicit experience/knowledge that this should /
    should not work?

    In the past, I've been into various printing tricks: redirecting the
    print jobs to a file, to a network printer via Samba or LPR (Microsoft
    built-in or 3rd-party spooler), to a local XP-borne GhostScript
    installation... I'm pretty sure I could redirect the HP LJ III
    driver's output harmlessly into some sort of common "virtual pipe"
    along those lines - and then maybe forward the traffic back to the USB
    device by some other means.

    At a first attempt, I can see that the USB device doesn't respond to
    the PRN or LPT device names. Is there any way to reach the USB printer
    port by some common device name from the Windows command line? Or, for
    that matter, a simple way to open the raw USB LPT port from Windows
    user space programmatically, via the Win32 API?

    At the hardware level, I don't think the LJ III would use some non-
    standard signaling, that would require direct software access to the
    LPT hardware. Quite the contrary - to me, the LJ III is a "mother of
    all printers", a reference printer implementation. If you attach just
    anything to its Centronics port and start sending bytes of data, using
    the Strobe and Busy signals in a vaguely standard way, you just have
    to get some output :) I would expect that any USB/LPT converter
    provides at least this much.

    Any ideas are welcome :)

    Frank Rysanek
    Frantisek.Rysanek, Dec 2, 2008
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  2. Frantisek.Rysanek

    Arno Wagner Guest


    I do not really know what to do under XP, but maybe you can use
    Linux to see whether it can work at all. With KNOPPIX or another
    live CD you can do this without installation. It is possible that
    the dongle and the LJIII are incompatible.

    Arno Wagner, Dec 2, 2008
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  3. Frantisek.Rysanek

    Hari Seldon Guest

    You can - but it will cost you - order an usb to LPT cable.
    Hari Seldon, Dec 2, 2008
  4. Does this setup also require that LPT be enabled in BIOS
    (perhaps not done if you have up to now worked only via USB)?
    Don Phillipson, Dec 2, 2008
  5. Thanks to all who replied... First of all, the bit of information
    about Prolific 2305, that was a misinformation - not true - courtesy
    of the dongle vendor. Now I can't find that note on their web site
    anymore. The actual chip used on the inside is a WinChipHead CH340S
    (or so the label says) - although by function and pinout it would more
    closely resemble a CH341.

    It shows some signs of life both in Windows and in Linux (usblp.c) - I
    do get some data printed on paper, fairly garbled (the Windows test
    page). It seems as if the dongle expects bidirectional communication,
    but reading back the printer status somehow always fails. Both Windows
    and Linux throw error messages along those lines.

    It fails exactly the same way with LaserJet III and LaserJet 6P.
    I've even tried improving power rail filtering inside the dongle, to
    no avail.

    I've posted a more detailed request for help to linux-
    . If those gurus don't help (I hope they don't
    blacklist me right away for offtopic questions), I guess hardly anyone
    else can help me :)

    Frank Rysanek
    Frantisek.Rysanek, Dec 23, 2008
  6. Frantisek.Rysanek

    Arno Wagner Guest

    Sounds like a parial or broken implementation of the parallel
    port in the dongle.
    Good idea. They will not blacklist you typically, but they
    might lfame you. Handle that like any good flaming, just ignore

    Arno Wagner, Dec 24, 2008
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