GA-EX58-UD3R: Serial Port

Discussion in 'Gigabyte' started by Walt Gallus, Mar 19, 2010.

  1. Walt Gallus

    Walt Gallus Guest

    A cording to the manual the COMA header can provide one serial port
    via an optional COM port cable. Where can I get such a cable? I am
    living in Europe (Switzerland).

    Thanks in advance

    Walt Gallus
    Walt Gallus, Mar 19, 2010
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  2. Walt Gallus

    Paul Guest

    There are at least two standards for the adapter cable. In the
    past, these pages provided some info.


    DTK (as seen on Intel D845PT)

    Using this reference, we can compare. ( purchase here )

    "For all Asus motherboards, you can use our V1 cable.

    1. CD - carrier detect
    2. RXD - receive data
    3. TXD - transmit data
    4. DTR - data terminal ready
    5. GND - system ground
    6. DSR - data set ready
    7. RTS - request to send
    8. CTS - clear to send
    9. RI - ring indicator"

    So it would appear your Gigabyte board uses the same cable
    as an Asus motherboard would use.

    "... I definitely determined that the P4C800-E COM2 header needs an
    AT-Everex-Intel style IDC-10 to DB-9 cable (whew!)."

    So my guess would be, you need the AT-EVEREX one, which on FrontX is
    the V1 version.

    If you can purchase them as cheaply as the PCCables versions, in
    Switzerland, you could always buy one of each cable type, to be sure.
    For the PCCables, the shipping costs are likely higher than the
    product cost.

    You could go to your favorite web site in Switzerland and look
    for Everex or DTK, or even DB9, and try and find a reference to
    such an adapter.

    Paul, Mar 19, 2010
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  3. Walt Gallus

    Walt Gallus Guest

    This is the pin assignment of my GA-EX58-UD3R

    Pin No.










    No Pin

    I cannot (I am a complete non-expert) compare both assignments
    because the expression do not correspond. Can you tell which version
    is correct for me?

    Thanks in advance

    Walt Gallus
    Walt Gallus, Mar 20, 2010
  4. Walt Gallus

    Paul Guest

    What the Gigabyte staff did, was just copy the signal names from their design
    schematic, rather than using the common names (as you'd find on a pinout page).
    RXD or receive data is the same thing as SIN or Serial input.
    TXD or transmit data is the same thing as SOUT or Serial output.
    They're the same table. And as near as I can tell, the table
    is called "AT-EVEREX". It least the GND or ground, got the same name.

    1. CD - carrier detect NDCD
    2. RXD - receive data NSIN
    3. TXD - transmit data NSOUT
    4. DTR - data terminal ready NDTR
    5. GND - system ground GND
    6. DSR - data set ready NDSR
    7. RTS - request to send NRTS
    8. CTS - clear to send NCTS
    9. RI - ring indicator NRI

    The pins of the header, are labeled in the same order as the pinout
    tables you'll find on the web, like this one.

    If you look at the AT-Everex example here, where they
    show both connectors in the diagram, you'll see the wiring is
    not in natural order for direct connection to the connector.

    The tables give the impression the wiring is "straight thru",
    but to achieve the necessary interconnect, the ribbon cable has
    to be split in two, and wires soldered to the DB9. This is necessary,
    as otherwise the wrong pins would get connected. It is partially
    to do with the way the two connectors are numbered.

    (The AT-Everex has to be made by soldering. Then slide up the plastic hood.)


    The DTK pinout (*not* for you), seems to use a more clever scheme, in that
    a DB9 with IDT rear interface can be used, requiring no soldering.

    The thing is, the ribbon cable wires have to be adjacent to the things
    they're to be connected to. If we look at the DTK example:


    1 3 5 7 9
    2 4 6 8 10

    Ribbon cable numbering


    RS232 connector

    1 2 3 4 5
    6 7 8 9

    You can see, that if you were to just connect up the wires, in the
    order that they fall naturally, 1 goes to 1, 2 goes to 6, 3 goes to 2,
    and so on. It reduces fabrication cost, if no soldering is required.
    I believe the DTK pin ordering, allows a DB9 with ribbon cable (IDT)
    thing on its rear. You can see an example here, where the wires are just
    joined in the order that they fall into place.

    The connector on the right of this photo, uses IDT termination on
    the back of the connector. That allows cables to be made with a
    press, rather than requiring cheap labor to solder 9 wires to the
    back of the DB9 and slide the insulating hood over the solder area.
    The DTK should be cheaper to make.

    Anyway, I hope that isn't too boring. Any time this question comes
    up, I have to go back and review the available information again,
    to make sure I got the wiring right. I think the one you want is
    AT-Everex, based on the pinout table provided by Gigabyte. The AT-Everex
    uses soldering and a partial cable twist, to make it look like the pinout
    tables are linear and one to one. (The DTK solves the problem, by
    using an entirely different signal name ordering, on the motherboard
    header. Which is easy for the motherboard engineer to do. By doing it
    the DTK way, the adapter cable should be cheaper to make. There
    are no twists or cable cutting necessary on the DTK. Just press and ship.)

    Paul, Mar 20, 2010
  5. Walt Gallus

    Walt Gallus Guest

    Thank you very much, Paul, for these detailed and well documented
    informations. I appreciate your effort although your arguments ask
    somtimes too much of me. But if I get you right, you think I should
    look for the AT-EVEREX Version 1. If this is true I am embarassed
    because I cannot find a single supplier in Switzerland, not even in
    Europe. Ordering such cheap an article in the United States does not
    make much sense. So I am still looking for an reasonable solution.

    Thanks and regards
    Walt Gallus
    Walt Gallus, Mar 20, 2010
  6. Walt Gallus

    Walt Gallus Guest

    Walt Gallus, Mar 20, 2010
  7. Walt Gallus

    Paul Guest

    If you look at the wiring table given in C610_AK661.pdf,
    it is a DTK and is the wrong kind.

    P1 1 6 2 7 3 8 4 9 5 DB9 end
    P2 1 2 3 4 5 6 7 8 9 Header end


    I can see one with the 1:1 wiring table on Ebay. I think this
    one is Everex.ör_Kabel_Adapter?hash=item5191586929

    Mainboard Pin 1 2 3 4 5 6 7 8 9
    9-Pin Typ 1:1 1 2 3 4 5 6 7 8 9

    You also have the option of building your own cable. Or, go
    to a local computer store, and see if they can order one for

    Paul, Mar 20, 2010
  8. Walt Gallus

    Walt Gallus Guest

    what a pity :-(
    Thanks for your hint. It is not in my country but I'll try to order

    Walt Gallus
    Walt Gallus, Mar 21, 2010
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