Resetting factory defaults of ADT supplied Galaxy 16 plus alarm?

My Galaxy 16 has just come off contract but ADT say if I use it in standalone mode, they would need to come out if it needs to be reset. Obviously, the standard Galaxy must be able to be user reset so I assume that ADT put some proprietary firmware in? Is this how it works? Are standard chips available or do I just throw it away and get a new control box?