An Internet protocol camera, or IP camera, is a type of digital video camera commonly employed for surveillance, and which, unlike analog closed circuit television (CCTV) cameras, can send and receive data via a computer network and the Internet.
There are two kinds of IP cameras:
- Centralized IP cameras, which require a central network video recorder (NVR) to handle the recording, video and alarm management.
- Decentralized IP cameras, which do not require a central NVR, as the cameras have recording function built-in and can thus record directly to any standard storage media, such as SD cards, NAS (network-attached storage) or a PC/server.
IP cameras vs Traditional Cameras
In the traditional analog CCTV application, security cameras capture an analog video signal and transfer that signal over coax cable to the Digital Video Recorder (DVR). Each camera may be powered by plugging in the power supply right at the camera or by using RG59 Siamese cable which bundles the video and the power cables. The DVR converts the analog signal to digital, compresses it, and then stores it on a hard drive for later retrieval.
In the IP world, each network camera captures an analog image but immediately converts it to digital inside the camera. Some digital processing can happen right at the camera, such as compression and motion detection. The digital video stream is then broadcast over the local area network (LAN) using Ethernet (CAT5 or CAT6) cable. Power is supplied to the cameras through the ethernet cable via Power-Over-Ethernet (POE) adapters built into the cameras and at the (POE enabled) switch.
IP Cameras advantages
IP cameras differ from previous generation analog cameras which transmitted video signals as a voltage, instead IP camera images are sent using the transmission and security features of the TCP/IP protocol, which provides numerous benefits:
- Two-way audio via a single network cable allows users to listen to and speak to the subject of the video (e.g. gas station clerk assisting a customer on how to use the pay pumps)
- The use of a Wi-Fi or wireless network.
- Distributed intelligence such as video analytics can be placed in the camera itself allowing the camera to analyze images.
- Transmission of commands for PTZ (pan, tilt, zoom) cameras via a single network.
- Secure data transmission through encryption and authentication methods such as WPA, WPA2, TKIP, AES.
- Remote accessibility  which allows live video from selected cameras to be viewed from any computer, mobile smartphones and other devices (with sufficient access privileges).
- PoE Power over Ethernet to supply power through the ethernet cable and operate without a dedicated power supply.