Security Camera Monitoring and Control
Application: Remote Pan-Tilt-Zoom Control of Security
Cameras
Quatech Products Used: SSE-400D
1 Port RS-232/422/485 Serial Device Servers
Surveillance cameras are used for a wide variety of CCTV access control
systems. The video portion of the system has been technologically suited
for transmission over an Ethernet network for quite some time, and advances
in video compression technologies have made these systems even more economical
to implement. However, unless a fixed position, fixed focus camera is
all that is needed, the ability to control what the cameras could see--via
Pan-Tilt-Zoom controls--was limited to a local computer with a wired RS-422
connection to the cameras (at a maximum of 4000 feet distances).
Serial device servers cut the cord for PTZ control, and enable remote
cameras placed anywhere on an Ethernet connection to be remotely monitored
and controlled. Further, they enable a a single computer to control any
number of cameras from a central location via a network connection, just
as if each one was physically connected to a local COM port on the computer.
In the example above, four security cameras, located any distance away
from each other and from the security office, are connected to Quatech
SSE-400D RS-232/422/485 serial device servers. The camera's PTZ controls
are connected to the device server's serial port, which is configured
for RS-422 communication. Each SSE-400D device server is connected via
Ethernet to a network. An operator in the control room creates a virtual
COM port connection with each device server, and then uses security monitoring
software in conjunction with a joystick keyboard controller, to switch
between the cameras and to change camera angles and zoom as required.
This serial-over-Ethernet approach has many advantages. Most notably, it eliminates the expense of routing long serial cables
between cameras and controllers, it enables multiple computers
to access the camera PTZ controls--via a local network connection or even
over the Internet, and it permits network-enabling security camera control
system without any alteration to software applications designed to use
RS-422 communication.
Other Access Control Applications:
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