Appendix A-3
Open Circuit State (IDC): An open circuit is defined as the absence
of the end-of-line resistor, with or without a detector load.
Protected Premises: The physical location protected by a fire alarm
system.
Remote Master Box: An initiating device intended to send alarm,
supervisory, and trouble signals to a remote location at which
appropriate action is taken.
Short Circuit IDC State: A short circuit state exists when an initiating
device shunts a low resistance contact across the IDC. The contact
resistance is defined as 0-200 ohms.
Simple Code: A code consisting of a distinct number of pulses used to
indicate which zone (IDC) is in alarm. The number of pulses is the
same as the number assigned to the zone in alarm.
Smoke Detector: A device that detects visible or invisible particles of
combustion.
States (IDC): The state of an IDC is determined by the physical
condition of the wiring and devices connected to the terminal block.
There are four states associated with an IDC:
• Short (0-200 ohms)
• Current-Limited state (400-820 ohms), across the initiating
device circuit
• Normal state (defined as the end-of-line resistor in place with
the full range of line resistance and detector load).
• Open circuit state (defined as the absence of the end-of-line
resistor, with or without a detector load).
Style B: A method of connection for IDC that will provide a trouble
indication in the event of an open circuit on the wiring loop. Also
known as Class B.
Style C/Style E: An IDC point type. A trouble indication is provided
if a short (+ to -) or open circuit condition exists on the wiring loop. An
alarm is initiated if a “current-limited” state exists. Style C is two-wire;
Style E is four-wire.
Style D: A method of connecting initiating devices on IDCs that
provide multiple signal paths so that circuit operation is maintained
with a single open circuit or ground connection. A trouble indication is
provided in the event of an open circuit on the wiring loop. Also
known as Class A.
Style Y: A method of connecting notification appliances on NACs that
provide a trouble indication in the event of an open circuit on the wiring
loop. Also known as Class B.
Continued on next page
Glossary of Terms, Continued
Technical Manuals Online! - http://www.tech-man.com
To Next Page
Loading...
