OK, I think I see what is happening here. I over-simplified in my 
earlier explanation - audio-CDs actually consist of WAV files on the 
disk. CD & DVD drives have logic within them to decode these to analogue 
audio and put this out to the audio cable that you would then need to 
feed to your audio card.

If however the software you are using has the ability to automatically 
"rip" the tracks via the digital interface (the IDE cable) and then play 
them, back out through the audio card, then that's what is probably 
happening.

Some CD drives used to have play and track advance buttons on the face 
panel, which, if you had the analogue cable in place you could select 
and play the CDs tracks as long as you had power to the system - no 
software required.

I guess as all can now be done via the digital interface and software, 
the analogue cable is no longer required to be installed.

Cheers/2

Ed.

kevinjjcan{at}rogers.com wrote:
> Hi, I just inserted a CD of the Moody Blues, I assume that is an
ANALOGUE CD, and low and behold, yes there is audio.
>
> Nero just advises when disk info is requested that it is a CD. I don't
know of any other tool to advise more.
>
> So thanks Jimmy, for the advice.
>
> KevinJ.
>
>
> ----- Original Message ----
> From: "rallee2{at}comcast.net" 
> To: os2hardware{at}yahoogroups.com
> Sent: Saturday, April 14, 2007 4:47:29 PM
> Subject: Re: [OS2HW] Audio
>
> Just a guess......
> Do you have an HDCP compliant video card? There are new formats such
as HDCP wherin audio and video are transmitted on the same cable. I can't
recall offhand if DVI outputs have such capability but I have a GeForce
7900GT made by MSi that is fully HDCP compliant and apparently it can, with
proper connector/cable send both audio and video on the one cable. This
leads me to believe that modern DVD drives may send both digital audio and
video to the mainboard on the main cable. In addition my SATA optical
drive, a Plextor PX-716SA, has *no* audio connector at all on the drive! So
in this case audio is certainly sent within the normal signal lines on the
main connecting cable. Hope this helps some at least in suggesting what
must be occurring since it is certainly not wireless and as you said no
dedicated audio cable is present.
> Jimmy
> ------------ -- Original message ------------ --------- -
> From: Kevin Johnson 
>   
>> Hi All,
>>
>> I'm mystified, which is quite easy to do. I upgraded 'puter with 
>> PCCHIPSp4m800pro, intel 3.2 and included a DVD rw.
>>
>> This motherboard has AC97 audio. and here's the mystifying part, I
did not use a 
>> audio cable from the DVD to anywhere on the
>> motherboard or it's cards. The point is I can play a movie DVD
with SOUND. How 
>> is this possible???? ????????? ?
>>
>> The DVD player is straight run of the mill IDE (80 pin cable),
with the normal 4 
>> prong power cable.
>>
>> I did install a Geniatech AS8000 TV card which is HDTV capable and
works great, 
>> but it too does not require any audio connection, just fits in a PCI slot.
>>
>> Any or all clarifications would be appreciated.
>>
>> Dual posted because I don't know the answer.
>>
>> Regards
>>
>> KevinJ.
>>
>> [Non-text portions of this message have been removed]
>>
>>     
>
>   



 
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