This document provides an overview of CCTV (closed-circuit television) systems, including their components and purposes. CCTV systems use video cameras to transmit signals to specific monitors for security and surveillance. They can help reduce costs and crime while encouraging good behavior. The key elements of a CCTV system are cameras, lenses, monitors, a DVR or NVR for recording, cables to connect components, and storage devices to save footage. CCTV systems can be analog, using coaxial cables, or digital/IP based, using Ethernet cables. They have various applications like monitoring bars, cash rooms, hospitals, public spaces, and detecting theft or vandalism.