AND pay attention of all extension because more time the NBX rest in some devices in 3 digit extension.
You controll all devices extension:
PARK
(For Exaplme in my installation when turn to 3 digit PARK remain in 3 digit and aonly the way is remove all the extension in park menu, select auto discovery, and reboot the NBX, oterwise the NBX with feature CallPark didn't function
AutoAttenandt
Pay attention in dial plan if you are 500 and 5000 AA if the dial plan min and max digit for 5 is min 3 max 4...........