Software House iSTAR Edge - LED Operation Summary; LED Status Table

Inputs
18
NO/NC Double Resistor 1K
This is the traditional Software House method of supervision where 1K  is considered Secure
and 500 orare considered Alert. Notice that the wiring is different for NO and NC.
Figure 6: NO / NC Double Resistor 1K
This method will report:
 Short
 Alert (500 ohms)
 Normal (1K)
 Alert (2K)
 Open (>30K)
 Line Fault (Any unexpected value) Usually due to wrong value resistors or faulty
resistors.
For UL Listed products,
burglar alarms must be supervised.