Which 2 contact points on the S20 are for charging.

I lost my charging cable -  there are 4 contact points on the back of the S20,   which two are the + and - points for charging (the other two are for data).

It is too easy to make a charging cable with a couple of paperclips as the clamps,  while I wait for a replacement to be posted.

hint: any S20 owner thats handy with a multimeter could figure this out for me in a flash :)