FOA Guide
 




Fiber Optics, Premises Cabling and Coax Cables for CCTV Security Cameras And Systems

CCTV Surveillance Cameras

The usage for commercial electronic security systems has expanded greatly in the past decade, particularly surveillance cameras used in many applications.  Whether its for inventory/shoplifting detection, recording of visitors, or night time viewing the uses for video surveillance continue to grow.  It’s estimated that there will be over one billion surveillance cameras installed worldwide by the end of 2021.

While a video system can be planned in different ways, there are two technical constants that system designers need to keep in mind.  First is that every modern CCTV camera uses IP/Ethernet protocol for communication, and each camera will require power of some type to operate.

There are three ways to cable IP surveillance cameras those being UTP (
unshielded twisted pair) premises cabling (Cat5e/6), fiber optics, and existing (or new) coax cables.  Each type of cabling has its positives and potential limitations.


UTP - Unshielded Twisted Pair Cabling
Most installers are familiar with and are using Cat5E/6 four-pair UTP cable for camera connections.  One of the primary advantages of using UTP cable is that a single cable can both carry the transmitted video images and power the camera using the industry standard Power over Ethernet (PoE).  Installing single cables are less expensive than separate connectivity and power connections, and providing the power for the camera(s) from a central location can greatly reduce installation time and cost.  PoE enabled network switches can be purchased for much less than $100USD, and provide enough power for multiple IP cameras, based on their current consumptions.  It is quite important to calculate the maximum PoE current that will be needed for the connected cameras, and make sure that the powering source selected can do the job.

Many installations in commercial buildings can be simplified by using existing cabling. Most Cat 5E/Cat 6 cabling has been installed as part of a structured cabling system which assumes a cable backbone from computer center to telecom closets and then cables to individual desktops. Most companies now depend on WiFi wireless for connecting employees, leaving only high-volume users still connected on cables. Newer installations will have many cables above ceilings for WiFi access points.  In many buildings there may be plenty of unused copper cables that can be used for cameras or other security devices like door entry systems or other alarm equipment.

The limitations of UTP cable are the maximum lengths of cables that can be installed from the network switch to the remote device.   The EIA/TIA standards list a maximum distance of 100 meters (328 ft.) between the central switch and a connected device.  That distance sometimes can be extended using cables with thicker conductors or PoE powered signal boosters can provide multiples of the 100-meter length if needed.  Where the distance becomes critical is when the cables are used to both provide Ethernet connectivity and PoE power.  Longer metallic cables have higher resistance and voltage drop, and careful calculations are needed to assure reliable IP camera performance.  An important note is that many IP cameras have a day/night function where they can provide an image in low-light conditions.  Such cameras will need more power when in the “night” mode, and those numbers need to be used in PoE calculations.


Fiber Optics
Fiber optics is the connectivity of choice for a variety of communication systems, from telecommunications to control of factory machinery. Fiber works because it’s low attenuation and high bandwidth allow large connection distances, immunity to EMI/RFI, and huge bandwidth that can easily support any IP camera’s video output.  The bandwidth of fiber optics is large enough that it is commonly used in switch to switch “backbone” connections, where up to multi-Gbps Ethernet signals are being transmitted and received.

In most security system multimode fiber would be the choice for new installations.  Multimode fiber can provide up to two miles of distance in some applications, which is typically sufficient for most surveillance applications. 

Multimode is preferable because it is lower in cost for most premises applications. If is necessary to convert a UTP connection to multimode fiber for an IP camera or other network device, media converters are quite inexpensive, much less than $100USD for each end of a connection.  Install an inexpensive 4 or 8 port Ethernet & PoE switch at the remote end, and several devices can be connected to the headend switch at very long distances.  Multimode for cameras is particularly attractive for cameras that are mounted on the rooftops and outsides of buildings in geographic areas that often experience lightning storms.  While a camera may still get hit by lightning the electrical pulse cannot travel from the camera to damage the expensive head-end equipment, as most fiber cables have no metal elements.

The advantage of fiber optics for security and surveillance applications in many buildings or campuses is there are millions of unused (“dark”) fiber optic links that have been installed over the past three decades. Using existing fiber links can trim thousands of installation dollars off of a system proposal, increasing the likelihood of a successful application.

The reason there are so many unused fibers is that while typical Ethernet data communications uses two fiber links for transmit/receive, most fiber cables contain many fibers, installed for spares for future upgrades.  The lifetime of glass fiber is very long, so the fiber cables installed in decades ago may be as good as new cable installed today, and they can easily be tested to determine if they are still within current industry standards.  A simple flashlight or visible laser can provide a no-go test; if the light isn’t visible at the far end, the fiber may be damaged or has poor or dirty connectors.  If no light passes through, that fiber link needs repair or perhaps other usable “dark” fibers can be found. Of course the attenuation of the fibers should be tested with an optical loss test set (OLTS) before trying to connect equipment like cameras or media converters.

While multimode fiber is preferred for its inexpensive terminations and transmission devices, a client may have existing “singlemode” fiber links, particularly for long distances between computer rooms and/or buildings.  Such cables should be labeled as singlemode, and are perfectly usable for security and surveillance communications providing that the links to be used can be tested as functional and within industry standards. Singlemode media converters are readily available and cost effective, especially for longer links.

For new installations fiber optic cable is very easy to install if technicians have had some basic training, know how to carefully pull the cable by the inner aramid yard wrapper and not bend the fiber excessively during installation.  Connectors are easy and quick to install and simple testing will provide verification that a fiber link is functional.

Contractors should always ask about any unused fiber optic links within a building or campus.  Remember that the fiber may have been installed years ago, and there may not be any person at the client’s location presently who was involved in the original installation.  A bit of investigation in the customer’s telecom closet focusing on their fiber optic patch panel will usually tell the story.  If a fiber patch panel has twelve total connection ports, and two have jumpers connecting Ethernet communications, and the other connection ports have dust caps, it’s likely that there are ample dark fibers that can be used.  In that case, the client can dramatically reduce the installation cost of a system, allowing contractors to either reduce the cost of a system or upgrade the quality and quantity of IP devices to be installed while staying within the client’s system budget.


Coax Cables – New and Existing
There are tens of millions of coax cable connections that have been installed over the past forty years with many used to connect analog video cameras.  These cables can be readily adapted to IP and PoE connectivity for new cameras.  In many cases if cameras are being replaced the client will want to see the same views as their older cameras presented, so the same cables and camera mounting brackets can be used.  Inexpensive IP/PoE coax media converters can transmit 10/100 Ethernet and PoE over distances exceeding 400 meters.  As with the pre-installed fiber links discussed above, using existing cabling will dramatically reduce system costs as well as the time needed to perform the installation.  This can free up skilled technicians to install more systems in shorter time frames.

As with the fiber optics above, a key to using existing coax cables is the quality of the cabling and particularly the original installation of the connectors.  When surveying a current cabling system, if the old analog cameras are still operational the coax going to that camera is most likely usable for IP/PoE connections.
While there are a variety of testers and testing methods to verify the performance of coax cable links, a simple rule of thumb is to always replace the existing connectors on both ends of a link.  Using compression type connectors, while a bit more expensive, will assure proper connectivity to the installed devices over existing coax cables.


The Variety of IP Connectivity
From the information in this article it should be obvious that astute security system contractors will be aware of the potential uses of pre-installed cables, and actively search them out when surveying an existing building for a new system proposal.  And when long distance, resistance to EMI/RFI/lightning damage and big bandwidth are needed fiber optic cables can be readily installed to provide superior performance.


More on premises cabling


Contributed By: David J. Engebretson, President, Slayton Solutions Ltd.

Dave Engebretson, ESNT, CFOT, CFOS/O/T/S/D, CPCT, TTT is the president of
Slayton Solutions Ltd., a Chicago, IL company that provides online and instructor-led training in fiber optics and networking of security equipment.  Entering the alarm industry in 1978, Engebretson has designed, sold and serviced central station, fire alarm, CCTV, burglar alarm, and access control systems.  Engebretson is the contributing technical editor for SDM magazine, and has written four books on using IP-enabled security devices. He can be reached at slaytonsolutions-@-sbcglobal.net.




 




Table of Contents: The FOA Reference Guide To Fiber Optics




 


(C)1999-2020, The Fiber Optic Association, Inc.