The New Otis "Gen2" Elevators

I have a building in my district that recently had a Otis "Gen2" elevator installed.  This elevator is a counter weight belt driven elevator for a 4 story building.  The system has a back up battery power.  When the elevator loses electrical power, the batteries kick in to keep the elevator operational from what information I have read on it.  I am having a hard time trying to get a straight answer to when I shut off the disconnect in the main control room, is it disconnecting "ALL" the power from the car.  Any time I try to get an answer from Otis, they just state don't touch anything until a technician arrives which is usually 30 min. to an hour.  If anybody has any information this, it would be very appreciated as I am trying to put together a training class together for my department and other local departments.  Located on top of the left side of the car is also a little black box with a plexi glass cover on it.  Once you have the shaft doors open, in order to open the car doors, there is a very small black button you have to push in order to release the lock on the car door.  Has anybody had any experience with this?  Hope to back from you guys with experiences on the new "Gen2" elevators..