Barry Watzman wrote:
> 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.
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.)
http://i.cmpnet.com/audiodesignline/2006/09/Fig91.png
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.
7.3.3.15 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.
ftp://download.intel.com/standards/hdaudio/pdf/HDAudio_03.pdf
I don't have an HDaudio motherboard, as otherwise, I would have tested
it by now.
More info here on HDaudio:
http://www.audiodesignline.com/howto/homeentertainment/193000336
http://www.audiodesignline.com/howto/homeentertainment/193001403
Paul
>
>
> Synapse Syndrome wrote:
>> "Paul" <nospam.DeleteThis@needed.com> wrote in message news:em77k7$jag$1@aioe.org...
>>> Synapse Syndrome wrote:
>>>> <Markus22222.DeleteThis@gmx.de> wrote in message
>>>> news:1166469690.851364.243410@79g2000cws.googlegroups.com...
>>>>> I'm in trouble connecting the Front Audio on my Ausus P5B:
>>>>>
>>>>> The Case has a Headphone and a microphone connector with the following
>>>>> cables:
>>>>>
>>>>> 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
>>>>
>>>>
>>>> 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.
>>>>
>>>> ss.
>>>
>>> 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.
>>
>> 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?
>>
>> ss. >> Stay informed about: ASUS P5B audio front panel 
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