Maximum serial cable length??

["magnatizerr" <magnatizerr@xxxxxxxxxxxxx>]

A quick question,

I've got the opportunity to buy a 15" touch screen LCD monitor that
connects to the PC via a serial cable. I would like to mount the
unit in the kitchen to control the server which is in the attic
(approx a run of 15 meters).

Would this be possible??
Or
What would be the longest run I could expect?
Are there any amplifiers that would allow me to extend the signal?

Many thanks in advance

Magnatizerr