Where PoE is not used, centralised and local power are the two mainstream approaches, each with clear trade-offs.

• Centralised: a high-capacity supply or UPS in the equipment room feeds every position. Control is uniform, UPS backup is straightforward, and management overhead is low.
• Weaknesses of centralised: long runs cause pronounced voltage drop, so distant devices may run below rated voltage. A supply failure takes out every position, and mixed voltage requirements are hard to satisfy from one source.
• Local supply: an individual adapter or small power box at each position keeps voltage drop small and limits the blast radius of a fault, which suits scattered positions with widely varying loads.
• The cost of local supply: more power units and more failure points, with sealing and surge protection handled position by position, and considerably more maintenance work.

Recommended combination: centralised supply with UPS on the backbone, plus local supplies or small UPS units at critical positions — entrances, the equipment room, cash offices — for both reliability and manageability. Any scheme still requires conductor sizing and voltage-drop calculation.