There are some similarities between IP and analog cameras but IP cameras have some distinctive features.

Camera comparison table

Image sensor. IP cameras are equipped with the image sensor known as CCD or CMOS sensor, a semiconductor sensor that converts light into electrical signals.

Lens. A camera’s lens projects an image on the surface of an image sensor. It is one of the most important parts of a camera since the quality of an image is so dependent upon it.

Signal processor. A signal processor handles the signal from the camera’s image sensor, converts it into digital form and can improve camera image quality.

Microphone and audio output. An analog surveillance system does not allow transmitting sound unless a suitable cable is connected to the digital video recorder. There is no such problem with a network IP camera since it has an ability to detect sound by itself, synchronize it with video stream and send it for listening and/or recording over the same network. Some cameras support two-way audio that let the operators communicate with each other via intercommunication devices. Such devices are cheap and easy to install.

RAM (Random Access Memory) is used to store temporary files. Most IP cameras are equipped with a frame buffer. This is a part of RAM reserved for recording and temporary storage of video frames. The oldest frames are overwritten by the newest ones.

Flash memory stores camera’s settings, its firmware and other data that rarely needs to be updated.

Ethernet allows an IP camera to be connected to a 10/100 Mbps Ethernet network.

Wireless interface allows an IP camera to be connected to a Wi-Fi wireless network and makes surveillance possible where wired connection is impossible or complete portability is required.

Alarm inputs/outputs allow connecting alarm sensors to an IP camera. When a sensor triggers an alarm, the camera’s processor takes pre- and post-alarm images and can send them via e-mail or to FTP.

Each IP camera has its own unique IP address, a built-in processor and software, which allows it to function as a web server, an FTP server, an FTP client and e-mail client. Nowadays, most IP cameras offer such features as motion detection, alarm i/o and two-way audio.