Smart Features: Search for cameras with a motion sensor to send phone alerts, and a microphone for audio recording. ........................................ Number of Cameras: The number can be estimated based on the house's angles; for example, a house on one street needs at least 2 outdoor cameras, while a house on two streets needs 4 cameras. ........................................ Fixed cameras for traditional surveillance, or PTZ (Pan-Tilt-Zoom) for wide areas, and outdoor cameras resistant to weather conditions. ........................................ Prices. With communication, the price can be reduced. 2 cameras 950