This document provides an overview of CCTV (closed-circuit television) systems, including the different types of CCTV cameras, their benefits, and how they work. It discusses wired and wireless CCTV systems and describes various camera types - indoor, outdoor, IR day/night, dome, pan tilt zoom, bullet, vandal proof, hidden, network/IP, wireless, and high-definition cameras - and their typical uses. The document aims to explain CCTV systems and cameras for security and surveillance purposes.