If the intruder is Non-Altitude Reporting (NAR), TCAS will display only the range and bearing. It can issue a Traffic Advisory based on distance and direction of flight but will not generate a Resolution Advisory. TCAS assumes Non-Altitude Reporting (NAR) traffic is at the same altitude as your own aircraft.
TCAS does not display NAR traffic above 14,500 feet.
The NORMAL, ABOVE, and BELOW setting are for display limits only. The selection has no effect on TA or RA issuance.