8RDA+ Firewire Connector

Discussion in 'Epox' started by redehm, Aug 6, 2007.

  1. redehm

    redehm Guest

    I have recently purchased an 8RDA+ off of eBay. The motherboard did
    not come with anything but a driver disc.

    I am attempting to track down the pin assignments and the connector
    type for the internal firewire / 1394 header. Unfortunately it looks
    like EPoX's ftp server is down so I am having trouble accessing

    Short of asking a friend who lives in the US to buy one of the 1394
    back panels (I live in the UK, epoxstore.com does not ship to the UK
    from what I can tell), does anyone have any suggestions for connecting
    the 2x5 pin front-panel connector from my case to the motherboard?

    I have already attempted to use this 8x1 connector:
    but it is too big.

    Any suggestions would be welcomed.
    redehm, Aug 6, 2007
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  2. redehm

    Paul Guest


    Eventually, the FTP server will be available again, and you can
    verify the pinout. I suspect you'll find it is similar to the
    pinout on the left of this picture.


    TPA+/- is one differential signal pair.
    TPB+/- is the other differential signal pair.

    VP is +12V, and there are two pins to handle the maximum current
    expected by specification.

    GND in the picture, would correspond to VG, as mentioned in
    the standard. There are two GND pins to handle the max current.
    The position of the two GND pins, is also used for crosstalk
    reduction between TPA and TPB pairs.

    In a proper implementation, I believe VP and VG are supposed
    to be galvanically isolated from signal ground. On computers,
    VG is the same thing as GND. In practical terms, that means,
    if you are using "Firewire networking" between two computers,
    you'd want to plug the computers into the same power strip.
    That helps prevent ground differences from developing between
    the two computers.

    S-GND is intended to be the shield ground, and connects to
    the outer foil on the cable. That is intended to contain
    emissions that might escape the cable.

    So when the Epox site is available again, verify that the pinout
    is the same as the above figure. The FrontX CPX105-2 part might be
    a good match for the job.

    To convert a 1x8 to a 2x5, you need a nylon shell from this page.


    The cpx075-4 for example, is a 2x5 shell. You move the wires and
    pins, from the 1x8 to the 2x5. You may be able to scavenge a 2x5
    from another cable assembly, if you have a lot of old motherboards

    This page, shows how to move wires from one shell to another.


    Paul, Aug 6, 2007
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  3. redehm

    redehm Guest

    Paul, many thanks for your help.

    Just to clarify, my case connector is the 2x5 one listed on the FrontX
    site (CPX075-4). The problem is that the header on the 8RDA+
    motherboard is an "unconventional" 1x8 pinout. It is too small for
    the CPX075-7 part that I have already bought (a 2.54mm pitch). The
    closest thing that I have come to is the back-panel connector that
    EPoX sells:


    You can just make out the white connector out in the photo. As a last
    resort, I can buy this soley for the connector, but would like to
    avoid it if I can get the connector on its own.
    redehm, Aug 6, 2007
  4. redehm

    Paul Guest

    Measure the spacing from pin to pin, to get an accurate idea of the spacing.
    The FrontX stuff could be 0.1" centers or 2.54mm. The Epox could be 2mm
    spacing, which is a tighter pitch.

    If could be that the pins are not interchangeable between the two systems.
    The pins used on the 2mm system, could be different than those used on
    2.54mm system. The retention of the pin, relies on its outer dimension,
    and if the pitch of the pins is tighter, the pins themselves might be different
    as well.

    Outfits like Digikey.com or Mouser.com have a ton of stuff like that. So
    much stuff, in fact, that it can be virtually impossible to identify just
    the right one.

    At this point, if Epoxstore has what you need, then buy it. Crimping
    new pins on the end of the cable, just isn't worth it. I looked through
    my copy of the Digikey catalog (2105 pages), and I cannot find a
    single row 2mm nylon housing and associated crimp pins.

    Paul, Aug 6, 2007
  5. redehm

    redehm Guest

    Measured the pitch on the header last night. You were right, it is
    2mm and the pins are smaller than the ones used with the 2.54mm pitch
    connectors. I had a quick look on the two sites that you recommended
    as well as rswww.com and couldn't find anything similar. And ya, I
    don't think that I want to go through the whole crimping exercise.

    My plan is now as follows:
    1. Buy the back-panel EPoX Firewire connector via my friend in the US:
    2. Buy a "6-pin male 1394 socket" to "2x5 header connector male"
    adapter cable from FrontX:

    Bit of a round-about way of doing it but it should work.

    I'll let you know how I get on. Thanks again for your help.
    redehm, Aug 7, 2007
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