With the advent of digital video, many of these problems have been solved. Digital signals are made up of 1's and 0's, sort of a Morse code that designates the state of information. IP data packets can travel over longer distances without becoming distorted. The digital video data can also be stored on a server or DVR (digital video recorder) with mammoth capacities, eliminating tapes while providing pinpoint accuracy to the process of event searching. Most importantly, digital video can be networked, enabling it to be sent over the Internet or Ethernet locally via a LAN, as well as be integrated to access control and other building systems.
Cabling for networked systems are typically CAT5e or CAT 6 twisted-pair. These cables transmit the image, control pan, tilt, zoom, and increasingly provide camera power through PoE (Power over Ethernet). In schools and other larger facilities, twisted-pair based networks are oftentimes already installed, making the "piggybacking" of an IP-based video surveillance system on the network feasible. IP cameras, featuring built-in servers each assigned their own address setting, replace analog cameras. Like any other network device, from printers to PCs, IP cameras are simply plugged into the network.
The biggest downside to an IP-based system is that it requires a close working relationship between the IT department and the installer/integrator. Combined with the higher cost of the equipment, this has made IP surveillance less attractive to small and middle market customers who continue to opt for traditional CCTV or for newer hybrid systems that combine analog with digital, such as a DVR that records already installed analog cameras.
Electrical contractors dipping their toes into the video surveillance waters are strongly advised to pursue technical training. A learning curve needs to be traversed, not only in appropriate workmanship, but also in proper system design, in ever-changing privacy laws, and to build an overall knowledge of IP-based data communications. Contractors are also increasingly expected to know how to specify the right camera, recorder and software to meet the needs of any given application.
The National Electrical Contractors Association, Bethesda, Md., offers training, along with its "Standard for Installing Closed-Circuit Television" installation standard for electrical contractors. Security equipment manufacturers also offer seminars to build the contractors' skill set.
The author is director of sales and marketing, Surveillance and IP Video Products/Imaging Systems Division, Toshiba America Information Systems Inc., Irvine, Calif.