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  • DIY Laplink cable results

    From kirkspragg@21:2/150 to All on Fri Aug 15 21:15:35 2025
    Hi everyone, hope your weekend has started off well & that your weekend is good to you.

    So i got round to putting together the 5m long laplink parallel port data transfer cable. I ended up using the 'Parallel Transfer Mode 0' cable schematics from docs.kernel.org/networking/plip.html and used 3 parallel runs of some cheap 4 core shielded speaker wire from our local hobby electronics store:
    https://www.jaycar.co.nz/4-core-round-screened-audio-cable/p/WB1510

    Soldering 12 wires from 3 different multi-core cables into the DB25 plugs was a bit of a hassle & with three runs of cable between the plugs. The cables barely fit in the plug housing -but they did fit with some light encouragement. I just tested it out & it works!

    Getting around 20KB/s between dosbox running on my main PC and my 386DX40 & I think that a reasonably speed to get form the old standard parallel port in my 386, I'm stoked!

    Supposed I should put together a serial null modem cable and try that out as well. I expect the speed will be quite a bit less.

    ... A friend asks only for your time, not your money.

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  • From poindexter FORTRAN@21:4/122 to kirkspragg on Sun Aug 17 07:58:03 2025
    kirkspragg wrote to All <=-

    Soldering 12 wires from 3 different multi-core cables into the DB25
    plugs was a bit of a hassle & with three runs of cable between the
    plugs. The cables barely fit in the plug housing -but they did fit
    with some light encouragement. I just tested it out & it works!

    My first IT job had me soldering 100 DB25s onto some kind of shielded cable, forget what type. It was a pain, but at least it was one cable per
    connector!



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  • From kirkspragg@21:2/150 to poindexter FORTRAN on Mon Aug 18 12:53:00 2025
    My first IT job had me soldering 100 DB25s onto some kind of shielded cable, forget what type. It was a pain, but at least it was one cable per connector!

    That would have made it a bit easier, did you have a decent soldering setup to help you hold the connector & cable in place while soldering together?

    I kinda made do with my basic temp controlled iron and a single bench clamp to hold the plug.... next time i'll have 2nd clamp of some sort to hold the cables. Its far too fiddly and error prone otherwise - I only slightly melted the plastic of one of the plugs when I slipped with the iron. Man am I out of practice wielding a soldering iron!

    ... Help! I've fallen and I can't Hey! Nice carpet!

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  • From poindexter FORTRAN@21:4/122 to kirkspragg on Mon Aug 18 13:14:47 2025
    Re: Re: DIY Laplink cable results
    By: kirkspragg to poindexter FORTRAN on Mon Aug 18 2025 12:53 pm

    That would have made it a bit easier, did you have a decent soldering setup to help you hold the connector & cable in place while soldering together?

    A pair of vise-grips. :)
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  • From Bob Worm@21:1/205 to kirkspragg on Tue Aug 19 19:48:31 2025
    Re: DIY Laplink cable results
    By: kirkspragg to All on Fri Aug 15 2025 21:15:35

    Hi, kirkspragg.

    So i got round to putting together the 5m long laplink parallel port data transfer cable.

    I just tested it out & it works!

    I just wanted to let you know that you're my personal hero :)

    BobW
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  • From Retroswim@21:2/121 to kirkspragg on Wed Aug 20 11:10:12 2025
    Getting around 20KB/s between dosbox running on my main PC and my 386DX40 & I think that a reasonably speed to get form the old standard parallel port in my 386, I'm stoked!

    Hell yeah!

    What transfer software are you using? Back in the day, we used a package called "FastLynx", it could get around a megabit of throughport between 486es, using a standard LapLink parallel cable. I have to assume using some
    form of compression?

    Cheers,
    RetroSwim

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  • From Bob Worm@21:1/205 to Retroswim on Wed Aug 20 21:04:57 2025
    Re: DIY Laplink cable results
    By: Retroswim to kirkspragg on Wed Aug 20 2025 11:10:12

    What transfer software are you using? Back in the day, we used a package called "FastLynx", it could get around a megabit of throughport between 486es, using a standard LapLink parallel cable. I have to assume using some form of compression?

    Every time anyone mentions Laplink I go off into a mental rabbit hole and think that I might have to whip out the ol' logic analyser and sniff a Laplink connection to see how it works. My cheapo logic analyser only has 8 pins, though, so I guess it'll have to be serial. At a guess parallel would use the same protocol over the top.

    Maybe it would be easier to MitM it using a system with two serial ports. If it relies on hardware handshaking, though, I might have to bypass those through at first.

    Hmmmm...

    BobW
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