The Digital Security Advantage

Piece by piece, school districts across the country are upgrading from analog security closed circuit television systems to digital surveillance systems. The result is better quality surveillance and higher quality security.

Carroll County Public Schools (CCPS), based in Westminster, MD, has replaced analog video tape recorders with digital disk-drive storage devices, opting to stick with analog cameras for the time being.“You can store a lot more information on a disk drive than on a tape,” says Larry Faries, coordinator of security with CCPS.“Tapes don’t need to be changed, and no one forgets to change tapes. The video is easier to review on disk. You just type in a date and time, and the video comes up.”

By contrast, security officers must wind through hours of videotape footage, stopping periodically to review frames, to locate materials necessary to an investigation.

At Annapolis, MD-based Anne Arundel County Public Schools (ACPS), Edward G. Piper, supervisor of Security is also upgrading from analog to digital and installing new digital video recorders (DVRs) as well as digital cameras. “The new cameras are Web-enabled, so you can access them from a computer no matter where you are,” Piper says.

To the south in the Huntsville, AL, School District, city schools suffered $6 million in fire, theft and property damage during a period of three years. Property insurance costs had risen to $1 million per year.

Today, an advanced digital surveillance system by GE has enabled the district to monitor video across the district from a single central security station. Monitors installed in principals’ offices also allow local administrators to view areas in their schools and head off problems as they arise. Sharp Communication, a local security consultant and integrator, designed the system to send time-lapse video from various schools to the central security station on schedule or on demand. The remotely monitored digital system has reduced the number of incidents, cutting insurance costs by $900,000 per year.

What’s the Difference Between Digital and Analog Surveillance Systems?

At one time, all systems were analog, meaning that electrical signals — currents or voltages — were manipulated to create an electrical analogy of a picture or a sound. Electrical signals, of course, can travel through wire or even the air at the speed of light. At the receiving end, electrical equipment would recreate the video picture and the sound from the electrical analogy. An analogy by definition, however, is not an exact copy. It is something similar but not identical to the original. Analog signals then are not always precise. In fact, they are only as precise as the integrity of the signal that arrives at the receiver. Distance, transmission media and other factors all degrade analog signals and make it more difficult to see or hear exactly what the sender intended.

Not so with digital signals which encode information in combinations of zeros and ones. If the signal gets through, so does all of the information. Computer systems can then decode the zeros and ones and recreate the original picture or sound exactly.

Digital Advantages

The exactness of digital technology makes it possible to improve the quality of video surveillance transmissions, as well as the quality of security system performance.

A simple example of the advantage of digital technology that many districts have already benefited from — digital information can be stored on the disk drive of a digital video recorder. Videotape is a linear storage medium. To access information stored on tape, a user must view the tape from beginning to end until arriving at the right section. But finding digital information stored on a disk, a non-linear medium, is much faster. A user need only tell the system the time and date when the video was recorded, and the system will instantly access that information.

In addition, digital cameras can easily be modified to transmit their information over network cables. That alone can save surveillance users hundreds, if not thousands, of dollars in costs generally required to purchase and install separate cables for analog camera systems. Network-enabled Internet Protocol (IP) cameras plug directly into a network.

Once the cameras are on the network, anyone with appropriate clearances and passwords can check video from any location in the world as long as he or she has an Internet connection. The principal can check camera video from the administrative offices, and the security director can check from a remote security office or a hotel room on the other side of the state.

“It is also easier to integrate digital video technologies with other security technologies, such as intrusion alarms, access control systems and fire systems,” says Robert Siegel, general manager, video and software solutions, with GE Security. “The digital world has a whole software infrastructure, and different systems can be made to talk to each other. So if a fire alarm goes off, cameras immediately send images from the area where the fire alarm went off.

“This kind of thing is much easier to do in a networked IP world than in the old analog world.”

Converting From Analog to Digital

Few organizations, let alone budget-constrained school districts, can afford to purchase all of the equipment and software required to switch from analog to digital systems all at once. But that isn’t necessary. The switch can be made piecemeal.

Siegel, for example, notes that it is possible to connect analog cameras to digital IP networks by connecting a device called a codec in between the camera’s output and the network. Short for encoder-decoder, a codec takes analog information and encodes or converts it to digital information that can flow across network cables. “Say you have 100 cameras, with 10 in critical areas that you want to be able to monitor remotely,” says Siegel. “You can buy a codec for $200 to $500 per camera.”

Codec technology, then, enables a school security director to maintain a perfectly good $1,500 pan-tilt-zoom analog camera for a couple hundred-dollar codec-connection to a network. Buying a new digital camera with the same pan-tilt-zoom features could cost a couple thousand dollars.

The Bigger the System, the Greater the Digital Advantage

The Lee County School District in south Florida encompasses 72 schools and has 80,000 students. As reported in Access Control & Security Systems, a security trade publication, some of Lee County’s schools were constructed in partnership with local governments and designed to share facilities.

Intrusion alarms in many of the schools had been set to activate when someone entered a facility after hours. False alarms became a huge problem. Digital technology, however, made it possible to issue access control cards with software keys that told the intrusion alarm systems not to activate when someone carded in using specially encoded cards. The system, provided by GE Security, reduced false alarms by 60 to 70 percent. The system is also used to refuse entry to deactivated cards.

At one time, Lee County employed a third-party company to monitor alarms on the system. By allowing alarm information to flow across the school district’s local area network (LAN), it was possible to set up an internal monitoring system in the district’s offices and to eliminate the cost of third party monitoring.

At the same time, Lee County’s Security Department set up a wireless digital system allowing the county sheriff’s department to tap into cameras in individual schools from police cruisers parked nearby, a technique designed to facilitate swift response to a life threatening emergency.

In the nation’s fastest growing school district, Clark County in Las Vegas and southern Nevada, more than 430 schools and school district buildings employ a GE digital security system. On average, each school uses two digital video recorders, each recording video from 16 cameras — that comes to approximately 7,000 cameras and 900 DVRs.

To make the move to digital, district security officials installed GE Security StoreSafe II combination digital video/multiplexer recorders (DVMRs). Legacy analog cameras were used until they could be replaced with GE digital cameras. New schools went immediately to digital cameras.

Of course, nothing’s perfect. If a digital IP system goes down, digital cameras can’t send video to storage devices, and the video will be lost. To avoid that problem, Clark County opted for an embedded system that ensures against lost video by connecting cameras to local DVMRs, which in turn, connected to the network. The configuration permits video to travel across the network to security officers while the network is up and running. But if something causes the network to shut down, the local DVMRs continue to record video that can be accessed when the network comes back on line.

If the network remains down for too long, school officials can access video by traveling to the DVMR where it was recorded and viewing it locally.

In the end, digital technology makes a security system begin to look more like a network computer component than a separate system. “As long as it is in a digital system,” Siegel says, “all of the video, all of the intrusion information, all of the bomb detection information can be captured and analyzed by software systems. That means that school district officials have a dynamic security environment that enables swift responses that could not be achieved before.”