Not a tech but the end user for a high rise bldg with 5 Schindler Haughton Gold Flight traction elevators. One (the freight) is the original equipment (26 years old) but the four passengers were modernized about 6 years ago with TXR5 controllers and Magnetek drives. I don't have to tell anyone here the predicament we got suckered into with this very proprietary controller, but I would like some suggestions as to what controllers (make and model) we could switch to that would be really and truly non-proprietary that any elevator service company could work on without the use of some tool, SDM chip or other device that the out-going service company will vindictively pull off the job once they know they're out the door. Thank you so much for your help!