In video surveillance systems, what is RS485 commonly used for?

RS485 is a standard used for serial communication that is often employed in video surveillance systems, particularly for controlling devices such as pan-tilt-zoom (PTZ) cameras. The reason this answer is correct lies in the characteristics of the RS485 protocol, which supports long-distance communication and allows multiple devices to be connected on the same bus. This is essential in surveillance systems where one controller needs to send commands to various PTZ cameras over significant distances without signal degradation.

PTZ cameras require precise control signals to adjust their positioning and zoom, and RS485 is particularly well-suited for this application due to its robustness and ability to handle multi-drop configurations, allowing many devices to communicate over a single pair of wires. This makes it an efficient solution for installations that utilize multiple PTZ cameras, allowing operators to manipulate the cameras from a central location.

In contrast, the other options do not align with the primary use of RS485. For example, video signals are typically transmitted using formats such as HDMI or coaxial cables, while Wi-Fi connections utilize different wireless communication standards. Power management in surveillance systems would use power over Ethernet (PoE) or dedicated power supplies rather than RS485. Thus, the use of RS485 for controlling PTZ actions is