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From: donm@hpnmdla.HP.COM (Don Montgomery)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Ringing CPU?
Message-ID: <11300002@hpnmdla.HP.COM>
Date: 8 Nov 90 23:40:02 GMT
References: <1990Nov5.210559.5733@maytag.waterloo.edu>
Organization: HP Network Measurements Div, Santa Rosa, CA
Lines: 12

Are you sure the ringing you're hearing isn't coming from the pc's speaker?
Depending upon how the speaker is driven, it may be digital noise being
coupled into the speaker-driver circuitry, with the pitch and volume de-
pendent upon bus activity.

I have a Heath Computer Voice Card (with its own speaker) in my '286 machine
that makes all sorts of interesting "space age" sounds due to bus activity
coupling into its audio circuitry.  Not loud, but enough to make a guest
user wonder what's going on...

				 Don Montgomery
                               donm@hpnmdla.HP.COM