So I'm wondering if anyone has any information about the Dell power supplies which have 3 contacts on the barrel.
I know the 3 are power, ground, and some sort of communication link. Does anyone know what the communication line is for and/or what kind of protocol it uses?
EDIT The reason I ask is I'm considering trying to build my own semi-advanced charger (not for a laptop but something else... it's a long story) and while I'm sure I could figure out a charging circuit given the internet as a resource, I was wondering what they use the communication line for and if it's necessary for my purposes. It seems the answer is no since I will be the only one using my device and thus don't need to worry about people plugging in not kosher chargers...