I had a tech set up the door box in the shop, we had the same results as before. I then had him hook the door box to a DSX40 (built in controller) and the door box worked. So we now know the door box is good and it must be the controller.

When we spoke to NEC tech support, they insisted we had another bad door box and the controller was fine. When my tech explained that this is the second door box we are trying and we have the same problem, they still insisted it was the door box.

Thanks for all that tried to help

Also,
the door box on the DSX is not polarity sensitive.

http://www.valentinesystems.com