cpu jumper on Aopen mx34

[Skidmark]

I have an mx34 socket 370 board running a celeron 366@550 right now. I just ordered a celeron II 566 and I'm hoping I can get it to run on my board. There's a jumper that has the options of: Celeron (now), Joshua and Coppermine. What should I set the jumper to for the celeron II 566? I know it's a coppermine core. And what is the jumper for? Setting voltage? There are no other places to mess with the voltages so I'm assuming so. I don't want to fry my new CPU so what's my best bet? Coppermine runs at a lower voltage right?