By: Don McClatchie

          The use of HD video cameras in CCTV is growing due to the many advantages they have over the traditional high definition IP camera use. They are becoming popular because the installer can use the existing coaxial cable once used for the standard analog cameras and in most cases the price of the equipment is much lower in cost than traditional IP cameras. Using the existing coaxial cable is sometimes necessary because many previously installed cables are buried in walls or under concrete making them inaccessible or very expensive to replace. So, adding new HD cameras without digging trenches or breaking into walls is a great advantage. Also, the installer does not have to configure a network connection for a two-way communication as is required by the IP type cameras. Perhaps of greater importance, the HD-TVI, and HD-CVI signals both being analog in nature can be cabled to much greater distances of over 1000 feet which is much further than the IP camera signal with its restriction of 100 meters.

          With all the advantages of the HD-TVI and HD-CVI camera standard comes some new opportunities, one of them is the ability to send contact relay control and telemetry information along with the video signal on the same coaxial cable without interfering with the High Definition picture information. So, you can place a push button at an entry gate with an HD camera to announce someone at the gate and then use the same video signal to send relay control to open the gate. This is possible because the new HD-TVI signal is analog in nature and incorporates Sync Pulses and a Vertical Interval similar to the old analog cameras that dominated the industry for half a century. You can send contact relay information for alarm systems or to control door and gate access using the new HD format Vertical Interval that is buried in the HD-TVI and HD-CVI signals. This contact relay information is sent continuously along with the video signal and will go anywhere the HD video signal is sent. It is possible to send contact relay signals in either direction on the coaxial cable allowing for both remote control and telemetry on the same signal cable.

          FM SYSTEMS, INC. has a product called ATU-2HD and ARU-2HD that allows you to put two relay contacts onto any HD-TVI, HD-CVI, PAL, or CVBS video signal for control and telemetry. These devices transmit and receive relay control contact switches encoded on the video signal over coaxial cable, and twisted pair wire. You can insert your alarm and control signals anywhere a HD video signal is being used, including optical laser transmission and wireless transmission of video. Alarm and control signals may be carried over any distance by the video signal. Tele-metering and control contact closures are encoded onto the video signal by the transmitter unit and decoded to relay outputs in the receiver unit.

          The ATU-2HD RELAY TRANSMITTING UNIT and the ARU-2HD RELAY RECEIVING UNIT together make up a 2 channel relay control system which can provide up to 7 alarm and control channels on any one HD video signal when used in multiples. The alarm and control signals are inserted onto the Vertical Interval of the video signal so that they will not interfere with the picture. If the video signal with its Vertical Interval is recorded, the alarm and control information will also be recorded and can be recalled at play-back provided that the vertical interval is recorded. If the video is played back into an ARU-2HD unit the alarm and control signals will be correlated with the viewed video events. For multiple units the operating channel can be set by the user in the field with the internal program selector switch.

          One contact input of the ATU-2HD can be used as a system alarm that will operate a relay in the ARU-2HD upon loss of power to either unit, loss of the video signal or loss of the transmission path (cable cut). In the event of power failure, the video through-put will not be interrupted. Contact closures at the ATU-2HD input will be repeated as contact relay closures at the ARU-2HD output.

          The units are housed in a Bone colored ABS enclosure that has a UL flame rating of 94-VO and is powered by 12 Volt DC power transformers (12 Volt AC power cubes are supplied with the units). The current draw is low allowing the units to be connected to the same power supply as the camera if needed. Both the transmitter and receiver have power ON/VIDEO ON LED indicators for easy set-up, and the ARU-2HD has an LED for each relay to indicate the position of the relay.


RELAY TRANSMITTER                             RELAY RECEIVER

For more information or to place an order a call: 1-800-235-6960.