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Thread: Perfect DB25 to RJ45 adapter!

  1. #1
    Join Date
    Nov 2007
    Location
    Cairns, Australia
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    Default Perfect DB25 to RJ45 adapter!

    Hey guys, got a show in about a weeks time that'll involve running the projector from a fair distance from the control desk.

    I've built DB25 to RJ45 boxes in the past, but they've been a bit flimsy.

    Well today I was browsing around my local electronics store website, and noticed these:

    http://jaycar.com.au/productView.asp?ID=PA0904
    http://jaycar.com.au/productView.asp?ID=PA0905

    RJ45 has 8 conductors, so:

    R
    G
    B
    GND
    X+
    X-
    Y+
    Y-

    Hoping to grab a few of these this afternoon, so I'll let you guys know what they're like

    Just thought I'd share and maybe save some people the bother of building their own boxes.

    Cheers,
    Dan

  2. #2
    Join Date
    Jun 2010
    Location
    Australia
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    Default

    What about the Interlock pair?

    Also, I made an 60M cable from 2 x Cat6 cables and I used lots of grounds!
    This space for rent.

  3. #3
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    Nov 2007
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    Default

    Why? You only need 1 ground

    As for interlock, I suppose you could channel that through one of the other lines, however, for the setup I have it's not really necessary. The lasers won't turn on if the cable comes disconnected, and no one is going to be digging through the case 6 metres in the air. Besides that, the power point it'll be connected to is run to a patching box just beside the control desk, easy reach of the power switch if anything goes wrong.

    There won't be any scanning even remotely close to the audience, it's being used for ground projection

  4. #4
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    Don't just think about the ground as a connection, it's all about ground resistance. More wires in parallel means less resistance.
    This space for rent.

  5. #5
    Join Date
    Apr 2006
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    Miami, FL
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    Default

    Quote Originally Posted by dnar View Post
    Don't just think about the ground as a connection, it's all about ground resistance. More wires in parallel means less resistance.
    plus using pairs as color/gnd helps with noise picked up on the cable (as would using +/- per pair)

  6. #6
    Join Date
    Nov 2005
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    We used exactly then at our last show - they work OK!
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  7. #7
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    Feb 2005
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    Switzerland
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    I used them but they aren't very solid... And the contacts went bad quite faster. So now I use standard ILDA cable again...

  8. #8
    Join Date
    Dec 2006
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    Scotland
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    Picked up some for PENNIES on ebay so have a new toy to play with

    any idea what distance it will work over ? what you pushed it to dave ?

    Paul
    In the beginning there was none. Then came the light - #1 UKLEM - 2007
    BUY UK LEGAL LASER POINTER :: NEW - Blue 460nm Laser Pointers

  9. #9
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    It depends on the impedance of your lasers and DAC. I know my laser-wave blue is about 1K Ohm, and the FB3 is like 100 ohms, so the voltage drop is already roughly down to 4.6V right out of the FB3. Throw on 30 metres of cable, it drops to about 4.52V. So if you are using the FB3, the largest drop is from the DAC itself, the cable is pretty insignificant. Wouldn't hurt to use a buffer though.

  10. #10
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    We were running over 100M of cat6 no problem. We do have high impedance differential receivers on all our lasers colour channels tho
    KVANT Australian projector sales
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    Lasershowparts- Laser Parts at great prices
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