Despite the fact that the L5200 and L7000 offer zone 1 as an End of Line Resistor supervised zone, the panel will not allow you to program this zone as a Fire or as a Carbon Monoxide zone. One reason may be that there is no current available on this zone to operate a 2-wire smoke detector, and there is no auxiliary power output on the panel for powering 4-wire smoke detectors or carbon monoxide detectors. It would be possible to operate a heat detector on zone 1, but because Fire is considered a life safety zone type, and having the fire zone type available for heat detectors only might cause confusion, Honeywell has chosen to err on the side of caution and not provide this programming option at all.