The single largest module in this program — every major device a fire alarm designer specs, from control panels down to NAC extenders, with purpose, operating principle, installation practicalities, applications, limitations, testing, and maintenance covered for each.
Earlier modules touched the control panel and a handful of detection technologies lightly, in passing. This module goes back through the entire device population in depth and in one connected pass: control panel internals (power supply, charger, SLC/IDC/NAC cards), every initiating device from spot smoke and heat detectors through beam and aspirating air-sampling systems to pull stations, waterflow switches, and tamper switches, every notification appliance and how candela and dBA are verified independently, the interface and amplification modules — monitor modules, control modules, isolators, relays, duct detectors, NAC extenders — that let the system reach outside itself, and finally power distribution, batteries, and remote annunciators.
This is deliberately structured content, not a photo catalog — every device family is covered as flowing engineering explanation, organized by function rather than as twenty rigid subsections, because that's how a real designer actually reasons about component selection. Later modules on circuits, design, installation, and testing all build directly on the device-level detail covered here.
Each free explainer above covers one narrow device comparison well. This module is the connected, exhaustive version of all of them together — plus device families none of them touch at all, like control panel internals, beam and aspirating detection, isolators, NAC extenders, and remote annunciators.