The 500s is still a good little box as long as you aren't using it to operate a motor :toke:
The only problem with the 500s is that it is unlikely that you will find a genuine one as out of 100 sold 99 of them are probably cheap an nasty Chinese clones :-Nooo
Mine is an old 2004 model, but it is genuine
If you are after a cheap entry level linux box i would look at the Technomate TM-500. Its a little more expensive compared to the DM500 but your guaranteed to get a genuine one and more importantly it will control a motor with no problems.
It also looks a lot nicer :-worship
:-beer
Nano