ASUS P5B audio front panel

Discussion in 'Asus' started by Markus22222, Dec 18, 2006.

  1. Markus22222

    Markus22222 Guest

    I'm in trouble connecting the Front Audio on my Ausus P5B:

    The Case has a Headphone and a microphone connector with the following

    EAR L
    EAR R
    LINE L
    LINE R

    The Asus P5B can be set to AC'97 or HD Audio. The Connectors look like

    ASUS P5B - AC'97
    Line out_L
    Line out_R

    ASUS P5B - HD Audio

    I've tried to connect in this way (but there was no function):

    CASE ASUS P5B - AC'97
    -------------- -----------------------------
    MIC-VCC ---> MIC2_L
    MIC-IN ---> MIC2_R
    GND ---> AGND
    EAR L ---> Line out_L
    EAR R ---> Line out_R
    LINE L
    LINE R

    Can anyone help me connect this audio? Thanks for your help!
    Markus22222, Dec 18, 2006
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  2. I have the same problem with my Thermaltake case, except instead of LINE,
    those two connectors are called RETURN.

    I guess that the case connections must be AC'97 and not HD Audio, but I hope
    the extra connections will allow some of the plug sensing that HD allows.

    I hope you (we) get an answer to this.

    Synapse Syndrome, Dec 18, 2006
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  3. Markus22222

    Paul Guest

    The wiring is AC'97. So you can use the AC'97 BIOS setting.

    In the above table, MIC-IN should go to MIC2_L.
    MIC-VCC should go to MIC2_R.

    Paul, Dec 18, 2006
  4. Hi Paul

    I haven't got around to open my case to try that out yet, but what are the
    other two wires for then? There are only sockets for earphones and
    microphone. Is there no way I can get the computer to automatically
    recognise when a mic or headphones have been plugged in?

    Synapse Syndrome, Dec 19, 2006
  5. The audio signal goes from the audio board to the headphone jack, which
    is a closed circuit jack, so if a headphone is not plugged in, it comes
    back and goes to the line out jacks. Otherwise, if a headphone is
    plugged in, the headphone gets the signal, cutting off the speakers. I
    suspect that "Ear" is the line carrying the audio signal to the
    headphone jack, and "Line" is the line carrying it back from the audio
    jack IF a headphone is not plugged in.
    Barry Watzman, Dec 19, 2006
  6. Markus22222

    Paul Guest

    But the motherboard is HDaudio, and does not use any returned signals.
    Hdaudio has enough output channels, that a separate output goes to the
    front panel headphones, and a separate output goes to the green Line_out
    on the back of the computer. (Item "A" and "D" in this picture.)

    AC'97 shared the signals. On AC'97, the codec was connected to EAR, the
    headphone jack returned the signals on the Return lines, and from the
    front panel header, the returned signal went to the green Line_out
    connector. That is why jumpers are used on real AC'97 FP_Audio headers,
    when the user is not using any front panel audio wiring. But no jumpers
    are present or necessary on HDaudio 2x5 headers.

    In the case of the new motherboards with HDaudio, there are separate
    outputs for front headphones and rear Line_out. So computer cases that
    still have return lines, the return lines don't have to be connected
    and can be left dangling.

    As for "automatically recognizing", I don't really know what they do when
    those sense pins are not connected. The standard has some words to
    say on the matter, but the typical datasheet is pretty silent on
    the matter. on PDF page 139 here, describes the possible capabilities.
    Jack sense is done with the (in this case disconnected) sense pins.
    But the impedance measurement function, is optional, and may not
    exist on all HDaudio codecs. If the function exists, then
    impedance measurements may be done under software control.
    The sound driver, could use the impedance measurement at
    1 second intervals, and poll to see if headphones are present.

    I don't have an HDaudio motherboard, as otherwise, I would have tested
    it by now.

    More info here on HDaudio:

    Paul, Dec 19, 2006
  7. Markus22222

    Markus22222 Guest

    Sorry, Paul, but the settings are not correct. When I connect like your
    advise, the front Audio and the front micro are both out of function.
    Additionally the normal micro on the back of the PC functions in a very
    poor quality, if the pins are connected as above.

    Any further ideas? Or is it possible, that a case and a motherboard are
    not compatible?

    Thanks for your ideas!
    Markus22222, Dec 29, 2006
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