DSC HS2128 Reference Manual page 22

Single End-of-Line (SEOL) Resistor
When SEOL resistors are installed at the end of a zone loop, the alarm panel detects if the circuit is secure, open, or shorted.
The SEOL resistor must be installed at the end of the loop for proper supervision.
To enable SEOL supervision, program section [013], options [1] and [2] to OFF.
Note: This option should be selected if either normally closed or normally open detection devices or contacts are used.
Figure 3-7 SEOL Wiring
The following table shows zone status under certain conditions for SEOL:
Table 3-5 SEOL Loop Status
Loop Resistance
0Ω (shorted wire, loop shorted)
5600Ω (contact closed)
Infinite (broken wire, loop open)
Double End of Line (DEOL) Resistors
When double end-of-line (DEOL) resistors are installed at the end of a zone loop, the second resistor enables the panel to
determine if the zone is in open, closed, tampered or faulted.
Note: Any zone programmed for Fire or 24-hr Supervisory must be wired with a SEOL resistor regardless of the type of zone
wiring supervision selected for the panel. If you change the zone supervision options from DEOL to SEOL or from NC to
DEOL, power the system down completely, then power it back up for correct operation.
To enable DEOL supervision, program section [013], option [1] to OFF and option [2] to ON.
Figure 3-8 DEOL Wiring
Note: If the DEOL supervision option is enabled, all hardwired zones must be wired for DEOL resistors, except for Fire and
24 Hour Supervisory zones. Do not use DEOL resistors for Fire zones or 24 Hour Supervisory zones.
Note: Do not wire Fire zones to keypad zone terminals if the DEOL supervision option is selected.
Loop Status
Violated
Secure
Violated
- 22 -