The IEEE 802.3af/at/bt power-over-Ethernet standards and their power budgets, choosing between PoE switches and midspan injectors, and how to calculate an accurate PoE power budget for a system with many powered cameras, readers, and controllers.
PoE eliminates the need for a dedicated electrician-run power circuit at every camera or reader location, but only if it is budgeted correctly. This module covers the 802.3af/at/bt standards and their negotiated power classes, PoE switch versus midspan-injector architecture, and cable/distance power-loss considerations that govern real installations.
A worked power-budget example shows exactly why building a budget from each device's typical draw instead of its negotiated class ceiling can leave a switch dangerously undersized the moment every outdoor camera's IR illuminators and heaters activate at once — precisely the failure mode this module is built to prevent.