The Mighty PoE
Media converters play myriad roles in today’s centric world
- By Frank (Skip) Haight
- Oct 01, 2019
The lowly media converter—the mainstream definition
was always an electrical to optical Ethernet
transmission device. Traditionally, it was considered
a device used to convert from copper media
to an optical fiber media and then back to copper,
usually to send the data longer distances than the standard copper
cabling can handle. But in today’s IP-centric world, media
converters work on lots of different types of media.
The three that this article discusses are fiber optic media converters,
extended distance media converters, and wireless media
converters, all of which are transmitting an Ethernet signal.
The Ethernet Band
Here’s a graphical example of each type. Since all of them are
transmitting Ethernet, they are all converting from a standard
copper CAT5 or 6 cable, which has a limitation of 100 meters, or
328 feet. An optical fiber media converter converts to a fiber optic
cable and then back.
Although an extended distance Ethernet media converter
stays on copper cabling, it’s converting from a standard CAT 5
or 6 to a non-standard copper cable, such as a coaxial cable or an
unshielded twisted pair cable, and then back to a standard cable.
A wireless Ethernet media converter works the same way as the
above types but it’s converting the Ethernet to a radio frequency
to be transmitted through the air.
This article is to help you in selecting media converters that
fit your application, so here are some important considerations.
Many applications are outdoors and not in climate-controlled
environments. Electronics don’t like to be cold or wet so a harsh
environment requires a hardened product that can withstand extreme
temperatures, condensation, transient voltages and other
environmental factors. A lifetime warranty on all hardened
products means the product will work now and as long as long
as it’s installed.
Because there are so many factors to consider when selecting a
media converter for a harsh environment, it’s important that you
select a good partner to help pick an appropriate product. Fiber
optic media converters. The number one benefit with this type is
the long distances they can carry an Ethernet signal. Standard
copper cat 6 cables only carry the signal 100m, but a fiber-optic
media converter can extend that out over 100 km or more!
The second most common reason for using a fiber-optic media
converter is to isolate the devices in an outside location from
lightning or other electromagnetic interference. Optical fiber does
not conduct electricity so any lightning strike or EMI will be isolated
to that location and not a carry back to the headend. These
are often used for very short runs in lightning prone regions or
Make the Right Choice
So how do you choose the right fiber-optic media converter? They
come in lots of different types so here are options you have available
to you. The first question is whether you need a fixed optic
version or a unit that uses a small form factor pluggable, or SFP,
that slides into the electronic unit and acts as your fiber optic
transmission and receiving piece.
Next, figure out what type of fiber will be used. There is multimode
or single mode. Then conclude whether it will use one or
two fibers to make the connection. Many systems used two fibers
so that you can send data one way on the first fiber and then in the
opposite direction on the second fiber. Also related to the physical
cable that will be used is the type of connector on that fiber.
There are ST, SC, and LC connectors, and here we have it shown
as a dual LC connector for the duplex fiber.
Ethernet runs at different speeds, so you also have to decide
what data speed you want running over that fiber. There is 100
Mb per second, 1000 Mb per second, also called gigabit, or multi
rate media converters that allow you to slide in either a 100 or a
1000 Mb per second SFP for flexibility.
You also have to decide on the form factor for the media converter.
They come in a mini size, a medium mini size, and a full
size that would fit in a standard 19-inch electronics rack. These
smaller units are good for fitting in small locations like enclosures
or the mounting arms/back boxes of IP cameras. The full size
variants can be shelf or wall-mounted, or slid in to a 14 slot card
cage with no modifications.
Consider All Options
The last option to consider is whether you need power over Ethernet
at the remote location for your camera or other IP device.
ComNet has options for 15 Watts, 30 W, or even 60 W for the
outdoor rated IP PTZ cameras. And of course, all units ship with
the correct power supply.
One application to note to consider with fiber-optic media
converters is pairing appropriate units. When using just one fiber
between the transmitter and the receiver you should pair an A
unit with a B unit. The model number will tell you which it is.
When you are using a duplex fiber optic cable between the transmitter
and receiver, both units have the same model number.
Let’s examine extended distance Ethernet media converters.
The main reason installations use them is a retrofit application
where are you are moving from an analog camera infrastructure
to an IP camera infrastructure. These media converters allow you to use the existing coax cable or UTP cable and now run Ethernet
on it instead of the analog signal, and it can represent a huge cost
savings versus pulling out the existing cabling.
The second most common benefit is being able to send an IP
signal much farther than the standard hundred meters over cat six
without having to switch to more expensive optical fiber cabling
and optical fiber media converters. Many extended distance Ethernet
media converters can transmit an IP signal over 2,000 feet.
The third benefit is a good reason installers choose this type of
media converter. Pass-through PoE allows one power source, like
a POE switch, power all devices on the line. Power is transmitted
from the PoE switch, powering both of the media converters and
also passing power up to the camera at the end of the line. This
makes for a much quicker installation and means you don’t need
to worry about finding power at the camera location.
Please note that the amount of POE you need at the end
of the line will affect the distances you can successfully travel
over any copper cable, so please consult our data sheets for specific
limitations. Although ComNet has several product lines
that perform this media conversion, our most comprehensive
and popular segment is Copperline® distance extending media
converters. It comes in 15- and 30-Watt models, various useful
form factors, five different ways to power the modules, and 1 to
16 channel units.
Consider the Expense
Last in the series of media converters are wireless Ethernet media
converters. This is a little different in that we are converting
the binary code of Ethernet from an electronic signal to a radio
frequency signal and then back again. The number one reason
people use wireless is, so the cabling infrastructure necessary to
carry the signal is not required. Trenching for new cabling is very
expensive, complicated, and difficult to accomplish in many environments.
This all represents a huge cost savings by using wireless
transmission methods. The second big benefit is the speed of deployment.
If you have power on site, the installation of a wireless
Ethernet media converter can be very quick and effective.
This application is a simple point-to-point solution. The Net-
Wave NWK 11/M and NWK1 kits include everything needed
to set up a wireless link. The kits are preconfigured in the factory
and MAC locked so that installation on the bench or in the
field is simple, quick, and reliable. These preconfigured kits have
allowed installers with no previous experience using Radio frequency
products to successfully implement a wireless Ethernet
media converter solution.
Since many of these applications are intended to be used in
harsh environments, it is imperative that you select a product
that can handle extreme temperatures and other environmental
factors. In addition, it’s important to work with a company that
has expertise in all types of Ethernet media
conversion and can work with you to determine
what solutions are best suited for your
This article originally appeared in the October 2019 issue of Security Today.