Application Note 06

There are critical security installations where it is desirable to configure a redundant video transmission system that will allow continuous images to be transmitted when there is either an accidental or intentional break in the interconnecting fiber or coax. It is also important to immediately detect the occurrence of such a break. The LuxLink RSW-1002 Redundant Video Switch has been designed expressly for use in such installations.

The above figure shows a typical application of the RSW-1002. At the camera end a BNC T connector is used to route the video signal into two individual fiber optic video transmitters. The fiber from these transmitters is then run to two independent fiber optic video receivers along completely separate paths. At the receivers, the two outputs are connected to the video inputs of the RSW-1002. One channel is designated the "primary" channel and the other the "secondary". The output from the RSW-1002 is then connected to the monitor or other video-recording device.

During normal operation both fiber optic video receivers deliver the same video signal to the two inputs of the RSW-1002. The RSW-1002 monitors both video channels and directs the primary video channel to the output. Green indicator LEDs on the unit monitor the presence of video signals on each channel.

Upon the loss of either video signal (e.g., a cut fiber or coax, loss of power to the camera or transmitter) the RSW immediately indicates an alarm condition and provides an output to trigger the optional ALM-1000, alarm-sensing module. If the video signal loss is on the primary video channel, the RSW switches the secondary video input to the output. If the loss is on the secondary video input, the primary input remains connected to the output.

The RSW-1002 operates directly with baseband video signals. As a result the RSW-1002 may be used with any video signal transmission system, whether fiber optic, twisted pair systems or plain coax to implement a reliable and inexpensive redundant video transmission system.

The drawing also contains the ALM-1000 Alarm-Sensing Module. During an alarm condition from any LuxLink transmission system, the ALM-1000 produces an audible alert and triggers a set of relay contacts which can be utilized for remote monitoring purposes (i.e., central station).

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