A modern Home Security System uses sensors, cameras and control panels that network with each other directly, so unlike older systems that relied on physical cables to connect each sensor, they do not require a physical wired connection between them.
Individual components are either mains powered and plugged into a wall socket (like the control panel), or are self-powered by movement such as door and window sensors, or, battery powered with long-life batteries. Self-powered and battery powered components therefore don’t have any wires at all.