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Video Imaging and Alarm Verification

One of the problems that plagues alarm companies across the country is alarm verification. Specifically, how does a company know whether the alarm signal

Video Imaging and Alarm Verification

Jul 1, 2000 12:00 PM,
Steve Filippini

One of the problems that plagues alarm companies across the country is alarm verification. Specifically, how does a company know whether the alarm signal it received is due to an actual break-in or the result of a strong gust of wind blowing doors open? The answer is usually, that they do not. Police agencies and guard services used to spend most of their time chasing down false alarms before they started cracking down on the security industry. Today, you need to be able to verify an actual breach of security to get a fast response from an agency.

Security systems are designed to provide a perimeter/interior line of defense against intrusion. If the perimeter is compromised, there are usually interior devices located throughout the premises that will detect further intrusion. Despite these precautions, however, the actual verification relies on a responding agency’s noticing the break in security and reacting accordingly. Security guards and police officers do the best they can, but there are times when a well-concealed point of entry may be overlooked.

The next solution might be to have a set of eyes watching over the business 24 hours a day, seven days a week. This extra set of eyes would be in the form of a video camera. Video camera systems are popular with and reliable to the security-minded customer. Large businesses and corporations spend thousands of dollars building rooms and putting video monitors in them for their security guards to watch. If the location is staffed 24-hours a day, then this arrangement is the way to go. If the business is smaller, then other means of monitoring the video images may be required.

Several companies offer video recording and image archiving systems, and many provide a means of transmitting those images to a remote monitoring center for alarm verification and response. Some do it well; others do not. When a good provider of this service comes along, it is definitely worth the time and effort to learn all about it.

DSC (Digital Security Controls) Security Products, in partnership with Sur-Gard Security Communications, has developed the “Downlook Automated Still-Frame Video Transmission System.” If the name sounds impressive, the Downlook system itself is even more so. The concept is simple enough; position a video camera to cover an area of concern, interface a perimeter or interior intrusion detection device, and wait for the pictures to show up at the alarm monitoring center.

We will first take a look at the hardware needed at the customer’s location. DSC provides the front-end interface and has integrated the technology in several of its security panels. Because there are other alarm companies and security panel providers who would like to use the Downlook product, there is a stand-alone application available. The stand-alone application uses the DSC 8400DL Digital Communicator, the DLM-4 (single-camera module) and the DLM-7 (up-to-seven camera module).

The DSC 8400DL Digital Communicator is an eight-channel device with normally-open or normally-closed trigger inputs. These inputs will work with most dry-contact triggering security systems or relays that are powered off of bell and siren outputs. The DSC 8400DL is powered by a PS-3085 power supply, which is a 3 amp, 12 VDC source that provides alarm outputs for AC failure detections.

The DLM-4 module has a resolution of 256 infinity 256 pixels and 256 grayscales to provide a clear, sharp image on the viewing monitor. This module will also support almost any black-and-white CCD camera available today. A single camera will capture four images and store them for transmission to the central monitoring center. This allows the alarm monitoring center to see more than one image when attempting to verify an actual alarm situation. Using a programmable feature built into the module, you can set the capture and storage spacing from 0.5 seconds to a maximum of 3.5 seconds to display a string of images from activation to time-out. If there is any tampering or disconnecting of a camera by persons unauthorized to do so, the DLM-4 provides a supervision output that can be interfaced with a security system.

The DLM-7 module connects to the DLM-4 module and provides a multi-camera operation to the system. With the DLM-7 module, you can expand up to seven cameras that are each activated by their assigned alarm zones. The DLM-7 activates a camera, and the DLM-4 captures the video images. Connections to the cameras and DLM modules are made using standard BNC connectors.

The DSC 8400DL Digital Communicator should be connected to a dedicated telephone line. This is recommended to avoid any chance of a signal communication clash from other devices that share the same line. The time it takes from activation to image display varies based on the reporting format selected at the premises unit. SIA and Contact ID formats compress the alarm and video information into packets of information for easy transmission and decoding. A signal transmitted in either SIA or Contact ID formats will take approximately 30 seconds to 40 seconds for the signal to be displayed at the central monitoring center, which is roughly the time it takes to make a telephone call that is picked up by an answering machine. Other reporting formats will take longer because of the signal structure and decoding process of the transmitted message.

That takes care of the transmission side of the system. As for the necessary hardware at the receiving end, the video image is transmitted into the central monitoring center over a standard telephone line into a Sur-Gard MLR-2 DG Multi Line Digital Receiver. This is the same digital receiver used to receive alarm signals from your security systems in the field. Installed in the back of the MLR-2 DG are MLRV-A modules. These interface modules provide two outputs, a coaxial video output off a BNC post and a PC output by a 25-pin video bus and 9-pin data bus. Video images transmitted to the video monitor and PC include the customer’s account number, camera number and number of video images that are stored and ready to be sent. The PC interface located at the central monitoring center consists of a standard 486 or Pentium PC with one or more ISA slots and a DLGB (Downlook Grabber Board) card. The PC must have at least 16 MB of RAM available, and to avoid system conflicts, it is recommended that no other applications be running when using this system. The software included allows video images to be displayed, saved, retrieved and printed if necessary. The screen is designed to display a maximum of eight images at a time and, depending upon the premises unit at the customer’s location, can be programmed to allow continuous viewing.

If all of that sounds confusing, it really is not. The operation is simple – trip the alarm system, and have your picture transmitted to the central monitoring center. All you need to worry about is the installation and configuration of the system located at the customer’s site. The professional monitoring center takes care of the rest.

I recently toured the General Monitoring Services facility in Long Beach, CA, which is a third-party monitoring center. Their staff was gracious enough to give me a demonstration of the Downlook system provided for the company’s customers. As I stood in front of the utility room, I was instructed to open the interior door and smile. Within minutes, my face was displayed on a viewing terminal along with three other images of my smiling profile. My image was then saved on the hard drive of the interface PC. This saved image can be easily retrieved for printing or e-mailing to the proper authorities.

So now the question that comes to mind is, “Why would I want to use this product?” As I mentioned before, verifying an actual alarm condition is not always easy. Some alarm companies rely on multiple alarm signals to confirm activity inside a business that may be closed for the night. Other alarm companies use mics located throughout the business to listen to the interior of the building. The monitoring center receives the alarm signal and listens for any sounds of glass breaking or doors being pounded open. This is actually a good idea, provided the business is not located near an airport or has anything that constantly generates noise from within. CCTV works well when someone is located on the premises at all times. Besides, 24 hour guard services can prove to be expensive, and who wants to pay for someone who will snap a Polaroid of an intruder and run it up to the police station for verification?

The Downlook system is professionally installed and professionally monitored to ensure quality service and support for your customers. If your customer is interested in this type of alarm verification, I recommend that you at least look into the Downlook system and see if fits the needs of the end user.

Both of these companies have websites that provide further information if you are interested. You may reach DSC at and Sur-Gard Security at

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