My TN Connection

Video security and surveillance is a hot topic these days and one cannot traverse through daily life any longer without being observed by a security camera at some point during the day. While the cameras themselves are highly visible, the video signal is typically transported back to a central monitoring location via a fixed cabling infrastructure that is often an afterthought due to its limited visibility. This cabling infrastructure is usually copper-based and in the ever increasing reach of today’s video security and surveillance systems, many security professionals are finding that the quality, bandwidth and distance needed to perform even the most basic surveillance is beyond the reach of coaxial and unshielded twisted pair (UTP) cabling.

In fact, even though IP-based video security systems are gaining popularity, they face a serious distance limitation of 100 meters (328 feet) or less over UTP cabling infrastructure. This poses an insurmountable hurdle when trying to monitor the many outreach locations of a typical surveillance installation.

While fairing slightly better in copper distance limitations, most analog-based CCTV systems prove effective and economical only if the coaxial cabling runs are held to less than 750ft (228m). Utilizing coax beyond that distance, however, poses a number of problems, some of which are not immediately obvious. To accommodate lengths greater than 750 feet (228 m), you must make certain that some provision has been made to guarantee the video signal’s transmission strength such as the use of signal amplification, ground fault correction and surge protection. Installing these items will inevitably increase the cost of the system considerably, making alternative cabling methods more attractive.

In fact, the use of fiber optic cable in video security systems will allow for cable runs of over 1500 meters (5,000 feet) on multimode and distances of over 10km (6.2 miles) on single mode cable. In addition to distance extension, fiber optics also presents a number of other unique benefits not present in either coax or UTP cabling:

• Smaller size and better tensile strength making it easier to install when pulling through conduit or in overhead cable trays

• High degree of security as fiber is inherently difficult to tap into or interfere with

• Immunity to electrical interference such as:
  • Electromagnetic interference (EMI)
  • Radio frequency interference (RFI)
  • High voltages found in fluorescent lights, card access door strikes and outdoor lighting systems
  • Induced voltages (ground loops) which causes picture distortion and audio interference

• Higher bandwidth

• Improved reliability and overall transmission performance

Next up in this series, we will be discussing how to integrate fiber optics into these video security networks through the use of media conversion.

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