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