Kensington Expert Mouse (trackball) Enhanced functions

Jeffrey W. Baker jwbaker at
Mon Oct 1 15:13:51 PDT 2007

On Mon, 2007-10-01 at 18:03 -0400, Donald Hellen wrote:
> I have a Kensington Expert Mouse 5.0, which is actually a trackball.
> Unlike the very latest ones, it does not have a scroll ring. It has 4
> buttons which I'll call left, right, top left, and top right. The left
> and right work as a normal mouse. The other two have no funtion in
> Linux using the stock mouse parameters. 

I used to use this mouse and here's my recollection: the mouse expects
to receive a particular string from the computer before it even bothers
enabling the upper buttons.  Don't take my word for this, but I think
the initialization string it wants is "em40".

If you are using the serial port you will be able to easily see the
initialization that the Windows driver does, if you run Windows inside
VMWare on a Linux host.  That's how I initially figured this out.

Sorry I don't have better recollection or a patch to send you.


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