|I couldn't quite understand which module you're referring to.|
If you are using D610, a simple Google search will yield that Fn + F2 should do it.
If you are using E6510, according to this manual, there's a switch on the right side (First page, #17).
"I'm tired. But then again I'm so hungry I can't sleep. But what's the point of eating if your sleepy?" - Sniff, The Moomins.