Taking advantage of dark fiber

For applications where the distance, bandwidth or image quality requirements strain the capabilities of standard IP CAT5/6 or coaxial transmission, one can select fiber optic transmission solutions. For example, you can get audio, data, video and combined solutions including an expandable transmission system with configurable data, audio and contact closure. There are fiber transmitters that are digitally encoded, highly expandable and flexible for fiber optics transmission systems. Data formats support RS-232, RS-422, 2-wire/4-wire RS-485, Manchester/Bi-phase and contact closures. Using state-of-the-art coarse wavelength division multiplexing or CWDM technology, they transmit up to 64 channels NTSC, PAL, or SECAM video, 32 channels audio, 32 channels data, 32 channels contact closure signal or eight channels intercom.

Among fiber optics advantages are:

- Better quality transmission
- No interference from lightning strikes, short circuits, "cross talk," EMI, RFI
- No interference from high voltages in fluorescent lights, card access door strikes and outdoor lighting systems
- Lightweight
- Stable within a wide temperature range
- Long service life
- More secure - not easily tapped into or interfered with
- Extremely high bandwidth
- Tech growth - ongoing developments increase the amount of data transmitted and
- Sometimes, already installed!

A good question to always ask is, 'how much dark do we already have?' Dark fiber or what some call unlit fiber refers to unused optical fibers available in buildings and throughout local, regional and national networks. A good guess is that there is an estimated 80 million dark fibers installed in North America, thanks to the dot-com bubble of past years, new construction practices and technological advances in getting more traffic through the installed base.

Often on the IT side, installers have almost always included extra fiber strands when installing structured cabling backbones between telecommunications closets and separate buildings. That's because the cost of individual fiber strands is quite low so extra strands have little impact on the budget. During installation, it's not uncommon to break a fiber, so spares are handy to have with the aim that enough usable fibers will be available. Additional spare fibers were often installed to future-proof an installation.

Thus, firms often may have existing fiber links not being used. Initial investment is cut and what installers call long cable pulls significantly reduced. Of course, there still needs to be testing of dark fiber before considering it for security video transmission. And, the type, quality and lengths of existing fiber links to be used as well as the style of connectors installed on each end of the link must be known.

A caveat: Typically, the IT department considers the dark fiber to be their property. Thus, it is always best to contact IT to find out if there is any dark fiber, determine how much there is, and ask if you can use some.

Of course, there always remains the debate between creating and maintaining a stand-alone security systems transmission infrastructure or piggybacking on the corporate backbone, including its dark fiber. However, it is not always necessary to select only one or the other; some designs can play it both ways.

However, an obvious outcome of a separate, dedicated IT infrastructure for video and other physical security applications is isolating that traffic from the general enterprise network. There are no "competition" or video quality issues and there is sometimes a finer focus on security system functionality and dependability.

Yet, there are technology advances both on the physical security and IT sides, such as higher speed general networking, video compression/decompression modes and analytics at the edge, which are tending to moot the standalone points. From organizational and budgetary perspectives, closer collaboration and sharing between security and IT are beneficial and being encouraged today.

Uniquely, with fiber, physical security can have its own strands in the shared fiber bundle, thus achieving a stand-alone posture while also being part of the overall enterprise infrastructure. The dark fiber often makes this a very beneficial pathway to follow.