Looking for some help with serial link for a 4000. The controllers were order for discrete inputs with no serial link not realizing the we need to have serial link for the car. When we change the program to COP serial the hall calls will not, they will set but not latch and drop after 5 seconds. When COP serial is turned off the hall calls will work but not car calls. We are thinking we need a program change for engineering to correct the issue. Any ideas?