Devices & Signal Flow: How the Panel Hears and Speaks
Every fire alarm system is a conversation. Initiating devices — smoke detectors, heat detectors, pull stations, waterflow and supervisory switches — tell the panel something has changed. The panel decides what that change means (alarm, supervisory or trouble) and, within seconds, tells the notification appliances — horns, strobes, speakers, low-frequency sounders — and the supervising station what to do about it. This module walks that conversation device by device, strictly from NFPA 72, with no wiring or addressing.
- Describe what each initiating device senses, what signal type it sends (alarm vs. supervisory), and what NFPA 72 requires the panel to do when it arrives.
- Describe how the panel activates each notification appliance and the NFPA 72 performance it must meet — pattern, level, flash rate, intelligibility, timing.
- Trace a complete signal path, step by step, from a pulled station on the second floor to horns, strobes, elevator recall and the supervising station.
Modules 1–3 are open to everyone. Create a free account to keep going:
- All 17 Learning Center modules with NFPA 72 code sections
- Module quizzes, quick checks and the capstone
- Your progress, scores and streak saved across devices
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Additional Resources
Adopted Code Editions — Verify Locally
Always confirm the NFPA 72 and NFPA 70 (NEC) editions adopted by your jurisdiction before using any concept from this trainer.
Working With Your AHJ
Engage the Authority Having Jurisdiction early. Local amendments and interpretations govern the final design.