Apilaire 8870

My EZ8 has lost the ability to show that there is a thermostat in the system. I replaced the thermostat and determined that nothing changed. I further can see that the ELKRP software can send the time and date info to the thermostat and it displays perfectly which leads me to beleive that the RS 232 conversion is taking place as it should. When I try to see the thermostat from a keypad, It states that it is not enabled. Any help would be appreciated.