Subject:     Re: DO NOT Recommend Apple's GV/56k Modem
Date:        9/7/98 2:29 AM
Received:    9/7/98 11:58 AM
From:        R. Brochner, 
To:          mike, 

Mike,

Here are more details on the modem problem:
>
>>2. In certain situations, the modem can cause a high pitch low volume
>>buzzing nose through the system's audio; and
>>
>I've not seen that with two different modems, 
>but I've not used external speakers on the G3.
>Do you have a rev 1 G3 or rev 2?
>(ati RageII+ or RagePro on mb)

I have a Rev. 2 G3, but the symptoms were seen on my prior Rev. 1 G3 as
well.  I do not know if they are present in the Rev. 3 G3.  Specifically, I
have a base model Desktop 233 G3 with an additional 1gb SCSI drive and
external speakers attached.  It has the AUDIO ONLY personality card (Rev. 2
also) into which the modem is plugged.
>
>I'll check for that whine you mention.
>
>Can you give me a specific test to do ?
>(Would I hear it in normal audio playback?
>Only with external power speakers? etc.
>

The problem occurs under these conditions:

1.  Sound Source set to "Internal Modem"

2.  Volume set to 5 or above (it is present at the lower setting, but just
not as noticeable).

3.  Use the modem to call another computer.  After the connection is made,
the modem will cease negotiation sounds and become relatively quiet except
for a very low volume high pitched background noise--which, by itself is
probably tolerable.  But once the modem starts receiving data, the noise
becomes different and louder whenever data is coming in.  A sound file is
attached containing both sounds.

4.  I have repeated this problem with three different modems, in both Rev.
1 and Rev. 2 logic boards and daughter cards, at different locations using
different telephone lines (to eliminate the possibility of some unique
electrical interference causing the problem), and with different sets of
speakers.  The problem is present with the built-in speaker just not as
noticeable.  With the built-in speaker, the volume must be set to 7 and you
must listen right at the speaker to hear the sound.

5.  The solution is to turn the sound source to CD.  It is just a minor
inconvenience, but I suspect that doing so does not physically eliminate
the problem but masks it from being heard.  I would be worried about using
the G3 for audio tasks while using this modem. 

6.  I noticed this problem because I used to listen to broadcasts over the
internet and do other things at the same time.  In doing so, I turned the
volume up a few notches and heard the periodic noise as the machine
received the Real Audio data.  At first I thought it was coming from the
disk access or a defect in Real Audio, but it occurs whenever data is
coming in and not just in Real Audio.

Let me know if you are able to replicate the problem.

-Ruben