A7N8X 2.0 and com port problem

Discussion in 'Asus' started by FireBrick, Jun 26, 2003.

  1. FireBrick

    FireBrick Guest

    This is a bit long so please bear with me.
    Computer A was a XP1700 on a Soyo board with a Via chipset.
    I used com 1 to control my Amateur Radio.
    It worked perfectly.

    I've upgraded to a Asus & XP3000
    I wish to use com 1 or com 2 to control my Amateur Radio but have no

    I've checked, both machines have EXACTLY the same settings, I/O addresses
    for com 1 and com 2
    But no joy.
    I'm fairly conversant with this topic so I do know how to check settings.
    The Asus board and Com 1 WILL work with other equipment such as a modem.

    It's not a wiring issue as I can rehook to the old computer and com will
    again controls the radio.

    I've checked bios obviously.
    But the onboard Asus com 1 AND com2 will not work with the radio as they did
    on the older machine.

    Same Windows XP drivers, in same directories on both machines.
    I'm totally stumped.

    Can their be a voltage difference between the two chipsets that would be

    Sure hope someone can come up with an idea.
    FireBrick, Jun 26, 2003
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  2. FireBrick

    Paul Guest

    It could be flow control signals. If the Radio uses flow control on
    RS-232, maybe not all the flow control signals are working properly
    on the new board. Flow control, baud rate, start/stop bits, or parity.

    In terms of voltage, RS-232 levels are something like +/- 3V to
    +/- 25V. Since the ATX PS has +12 and -12 supplies, it should be
    dead easy for the A7N8X RS-232 interface to have enough voltage
    to work. Some RS-232 products only have +5V and GND, and don't
    have any voltage conversion circuitry - these devices sometimes
    work on a very short cable, but long runs cause the device to
    not be able to communicate. So, _maybe_ in this case, the Radio
    does something like that (insufficient I/O voltage), but that seems
    hardly likely. (Products like that actually use a RS-422 chip
    single ended, and the result shouldn't work, but it does.)

    You need to make yourself a breakout box. Buy a male and female
    RS-232 connector of a type to match the computer. Wire all the
    pins straight through, leaving room to get a voltmeter on each
    wire. Place the breakout in line with the normal connecting cable
    and two devices. Compare static levels on old config versus new config,
    to see what is different. With the "no-mans-land" between -3 and +3,
    you shouldn't be seeing any signals but GND and shield_GND at
    zero volts. (Both devices need to be connected together, like
    they normally would be, so you can see what the signals are
    really doing.) My recollection is the resting state of data signals
    TX and RX is the opposite polarity compared to the flow control
    signals. Consult one of the many web tutorials for more info,
    because each time I debug one of these, I have to go back and
    reread it all.

    If you aren't into all that kind of work, there are also RS-232
    products that have a LED per signal on a little tester. Some
    of these devices also have test points on the top of the tester,
    so you can insert your multimeter and measure the voltage.
    While these are undoubtedly fun to have, I prefer good ole
    connectors, wire, and solder myself.

    I keep a whole bag of RS-232 converters and debugging tools
    around for occasions like this. There must be $100 worth of
    odds and ends in there.

    Have fun,
    Paul, Jun 26, 2003
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  3. FireBrick

    FireBrick Guest

    thank you for your reply.
    I've determined that the port IS working as I can use another program to
    control that port and the radio.
    Also the port cycles the radio during the computer start up as it
    initializes the ports.
    This leads me to think the problem is more with I/O addresses, irq
    utilization or drivers.
    Back to the drawing board.

    thanks anyway.
    FireBrick, Jun 27, 2003
  4. FireBrick

    Paul Guest

    Does the program that doesn't work with the Radio have a preferences
    panel in the interface ? Have you selected the correct COM port from
    the list in the preferences panel? Perhaps the COM port you want to
    use is marked as "busy", due to a conflict in the use of two programs
    that want to access the COM port at the same time ? It could be a
    software problem, but at a level above I/O addresses and IRQ.

    As a hardware guy, I would wire the TX or the RX from that cable, to
    the RX pin on another COM port. Then, point Hyperterminal to the
    second port, and observe whether any communication happens on the port.
    If you had two spare COM ports, you could look at both sides of the
    link at the same time, rather than just being able to see half of
    what is happening.

    Wouldn't it be wonderful if the OS had a snooping capability ?

    Just guessing,
    Paul, Jun 27, 2003
  5. FireBrick

    FireBrick Guest

    Yes the program has a setup panel.
    You can choose the com port and all it's settings.
    Settings between the two computers are identical.
    Registry settings between the two computers are identical as to that
    programs com port settings, I/O addresses and IRQ choice. (although it's PCI
    and IRQ's shouldn't matter.

    Other users of the program have the same problem but then others do not.
    It seems to be machine specific.

    If I choose the SIIG dual port pci add-on card and select one of those com
    ports, then all functions work correct.
    Now of course the SIIG card utilizes it's own drivers so it's tough to

    Other users of this program and the authors have been trying to figure this
    out for over two years.

    Thanks for the suggestions and help.
    FireBrick, Jun 27, 2003
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