There are at least two ways in which this can happen:

1.  Each mouse action or movement causes a brief burst of data bits on the
mouse cord.  It's possible that this passes close enough to the sound card
to induce a small current in the circuitry just before the amplifier.

2.  Received keyboard and mouse events go into a buffer of pending input
messages, which will hold 15 of them.  The system will "chirp" if there are
already 15 waiting events, and no room to add the latest signal to the
buffer.  (This almost never happens, unless the process that should be
reading events from the buffer has crashed or hung.)

David Gillett


On 11 Aug 2003, at 9:48, Howard Rubin wrote:

> I have a client using Adobe Premiere 6.5 on a clone workstation.  He doesn't
> use normal computer speakers.  He has a normal PS2 mouse, nothing exotic or
> fancy, and hears a squeak whenever he moves the mouse listening on his
> headphones!  Fortunately the  noise  is not being recorded on his
> productions.... but, has anyone ever come across this situation?  I have not
> visited the machine yet, obviously I will bring along a new mouse to try,
> but I cannot see how a mouse can affect the sound system like this.  Thanks
> for any ideas.
> Howard Rubin
> The Computer Doctor
> Fortaleza, Brazil
>
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