PTZ protocols control the orientation, movement and focus of surveillance cameras.
The communications needed to control the orientation and focus of surveillance cameras follow Pan-Tilt-Zoom (PTZ) protocols. Using PTZ protocols, a controller station can send instructions to remote cameras. Cameras send audio and video data back to the controller and to monitoring and recording stations. Among the many PTZ protocols used in the CCTV industry, the surveillance cameras manufactured by Sony are compatible with three protocols.
PELCO-P
In this older protocol, a separate data cable is required in addition to the one being used for video. Communication on the data cable is serial and at low baud rates (4800 baud is typical). A given controlled device may not receive commands from more than one controller.
PELCO-D
This protocol has mostly superseded PELCO-P in the last few years. A separate data cable is still required for control: a single RS-422 serial line may control up to 32 devices.
PELCO-G
This protocol incorporates the capabilities of PELCO-D plus multiplexers for the audio and video streams in the CCTV system. Multiplexers time-share a channel over a set of devices, following a simple round-robin scheduling policy or more complex policies specified by their controller.
Tags: data cable, surveillance cameras, audio video, control orientation, focus surveillance, focus surveillance cameras
