Tips on Selecting an Ethernet Media Converter

January 9, 2014 at 10:00 AM

L-com Industrial Ethernet Media Converter (DIN Rail mounting)

Fiber optic technology is taking the Ethernet networking world by storm. It is faster, completely resistant to EMI/RFI, and offers incredible distances between nodes.


But fiber is not quite ready for all LAN applications. In many cases it makes sense to keep a copper network intact and lay a fiber network over it. So, here we find a need in our industry for a device that will convert seamlessly between the fiber optic network and the copper network without loss of speed.


We call these devices Ethernet media converters.



Industrial vs. Commercial


Commercial Media Converters

The first consideration in finding the proper converter for your application is whether your Ethernet media converter will be installed in a commercial or industrial environment. A commercial environment would include a typical office or clean room, and an industrial environment includes places with dust, moisture, temperature variations, vibrations, and other complications.


We've gone over the differences between the two in regards to switches before, but the same rules apply for media converters. It is very important not to confuse industrial versus commercial converters. While an industrial Ethernet media converter can operate in a commercial environment, it costs more and generally supports features not commonly found in a commercial environment such as DC power. On the other hand, a commercial Ethernet media converter should not be used in an industrial environment as network downtime and system failure can occur.


Single mode vs. Multimode


Fiber Glass Types

There are two main "modes" for fiber optic cabling: single mode and multimode. L-com has a great tutorial and video with in-depth explanation. In general, a single mode system is more expensive, but also provides better signal strength over large distances (up to 100km or more).


Multimode is much more affordable and can be used in distances of up to 2km, depending on network speed and bandwidth. Again, don't confuse the two! If you are running multimode cable, you need a multimode Ethernet media converter; a single mode version will not work.


Fiber Optic Connector Types



Fiber optic cables have their own unique connector types. There's a good video explaining fiber connectors here. Unlike copper, fiber connectors are very difficult to install properly in the field, and there aren't many options for converting a connector type with a passive adapter (although L-com does carry ST-SC, ST-FC and LC-SC adapters, among others, on its fiber optic adapters page). It is best to match the connector type with the device so they can be easily connected and no extra loss is incurred.


Remember, L-com stocks hundreds of factory terminated fiber optic cables off-the-shelf. We can custom manufacture fiber cables without minimum order quantities and with very short lead times, so you don't need to re-terminate or adapt a mismatched cable.



Other Features


Before ordering your media converter, also consider things like mounting method (DIN rails, 19" racks or chassis, or just placed on a shelf), network speed (10/100/1000 Mbps), and how you will get power to the unit. A properly installed media converter can both future-proof and provide redundancy for your network for years to come!


Quick note: Installing Ethernet media converters may require other components as well, such as fiber optic cables, Ethernet cables, and racks and accessories.

Hot Stuff! Low Smoke Zero Halogen (LSZH) USB Cables

December 3, 2013 at 10:00 AM

Flammability and Toxicity Ratings on Different Cable Types





What would happen if your cables caught on fire?


There's actually much more to consider than the obvious flames and danger. Gasses you can't see and destruction to the inner cable conductors can endanger lives and destroy valuable communications equipment. 


To avoid that unknown, here’s a snapshot of USB cable jackets and looking into what yours is made of. Most commercially available cable assemblies have an outer jacket made from polyvinyl chloride, or PVC for short. Another alternative chemical compound that a cable's outer jacket can be made of is called Low Smoke Zero Halogen (LSZH), which reduces the amount of toxic and corrosive gases emitted during combustion.   


PVC is a durable, flexible plastic material perfect for most general applications.  If you were to buy a deluxe or premium USB cable, PVC is the type of jacket it would have. Yet for all of its benefits, PVC has some downsides- the biggest of which is the way it burns


Once PVC has caught fire it typically burns freely for a long while and releases toxic gasses in the process, including harmful halogens. In a building fire, the danger is that flames can burn along the cable jackets behind a wall and leap from room to room or floor to floor.   In most building fires the toxic gasses are not a big factor since occupants can get outside, and since USB cable is rarely run behind a wall, most manufacturers don't bother making them with non-PVC jackets.


But in some instances, a building fire isn’t the only scenario to consider.  Military and aerospace applications add another element to the danger:  people don’t always have outdoor access.  In fact, any application where people are working in close proximity with cable assemblies and cannot easily get ventilation in the event of a fire would require a special jacket material for the cables.


USB with LSZH Jackets


Though USB is not often run behind a wall and the USB standard is typically only used in peripheral-to-computer applications (including many in military and aerospace environments), having many PVC USB cables can lead to a dangerous situation.  LSZH cables, on the other hand, are self extinguishing. For that reason, L-com has made LSZH USB cables an off-the-shelf product, available for same-day shipping. 



Standard LSZH USB cables are constructed similarly to the premium line of USB cables: they have 20 AWG power conductors for maximum power transfer, and have 30 micro inches of gold on the contacts to ensure reliable connections through multiple mating cycles. Along with the standard type LSZH cables, L-com also carries a line of its "latching" USB cables with LSZH jackets.  These cables have small latches in the Type A connectors that lock the connector in place.


LSZH USB cables with Latches prove to be especially valuable in high-vibration environments such as in a military vehicle or in a device that is meant to be carried over rough terrain. Don’t overlook endangering personnel and valuable communications equipment by using standard PVC USB cables; LSZH USB cables might be better for your application.


For more information check out our ratings chart below, or this helpful video on cable flammability tests.


USB Flammability Ratings


Surge Protectors: Your Best Investment In Protecting Your Wireless Network

November 29, 2013 at 8:39 AM


A single bolt of lightning carrying up to 100 million volts of electricity has the power to rip through roofs, explode brick walls and destroy electronic networking/communications equipment! Don't be fooled into a false sense of security if you never receive direct strikes. Indirect lightning strikes on telephone and power lines can be just as catastrophic! Protect your valuable communications equipment with L-com's HyperLink® brand coaxial surge protectors.


Lightning Strike

A common question our customers often ask is, "Where is the best place to put coax surge protectors in my wireless network?" The examples below outline some recommended areas to use coax surge protectors to protect your valuable communications equipment.


  • - At the base of your wireless antennas (for integral connector models)
  • - At the connector end of the antenna pigtail (for pigtail antennas)
  • - At the ingress of a NEMA Enclosure
  • - Between any cable end connected to active equipment such as access points and RF amplifiers

*Always remember to ground the protector to EARTH ground via 8 or 10 gauge copper wire*


L-com's HyperLink® coaxial lightning arrestor and surge protector products are available in two types,Quarter Wave and Gas Discharge models.


Quarter Wave coaxial surge protectors are designed to pass the desired frequency while suppressing lightning surges, much like a signal filter. Lightning strike electrical surges which operate at low frequencies are diverted through the protector's short-circuit to the ground.


Gas Discharge coaxial protectors are a type of lightning arrestor which employs a replaceable gas discharge tube, which is a component containing a small amount of gas. The gas tube dumps extremely high amounts of surge energy directly to the ground of the protector. HyperLink® coaxial lightning arrestors are available for 0-3 GHz operation or 0-6 GHz operation.


Wireless LOS Terminology

November 28, 2013 at 10:00 AM

Why Line of Sight (LOS) is so important


Sample of LOS and Fresnel Zone Diagram

When designing an outdoor wireless network, ask yourself this: what is between point A (antenna 1) and point B (antenna 2)? This path between two antennas is referred to as the Line of Sight (LOS).


There are three main categories of Line of Sight. Full Line of Sight (LOS) is where no obstacles reside between the two antennas. Near Line of Sight (nLOS) includes partial obstructions such as tree tops between the two antennas. Lastly, Non Line of Sight (NLOS) is where full obstructions exist between the two antennas.


By determining the specific Line of Sight conditions in the WiFi network area you can then determine the correct type of wireless system to install.


Another common term to be aware of is The Fresnel Zone, referenced in the diagram above. It is is an electromagnetic phenomenon where light waves or radio signals get diffracted or bent from solid objects near their path. The radio waves reflecting off the objects may arrive out of phase with the signals that traveled directly to the receiving antenna, thus reducing the power of the received signal.


Line of Site (LOS) Overview Diagram

Print and post the above diagram.


For indoor wireless network installations it is important to consider obstacles such as walls, ceilings, and furniture that will affect Line of Sight since these all play a role in wireless signal reception. In wireless transmissions, reflections (when wireless signals "bounce" off objects) and multipath (when wireless signals travel in multiple paths arriving at the receiver at different times) are as important as signal strength in determining the success of an installation. A signal will also exhibit peaks and nulls in its amplitude and alteration of its polarization (vertical or horizontal) when propagating through walls, ceilings and reflecting off metallic objects. 


Path Loss is another area of concern when dealing with Line of Sight. For instance, although 2.4 GHz signals pass rather well through walls, passing through trees and leaves is a challenge. This is due to the difference of water content in each. Radio waves in the 2.4 GHz band absorb into water very easily, so the high level of moisture in trees or leaves would trap the waves. When faced with nLOS or NLOS conditions due to trees, 900 MHz is your best choice as it is not absorbed like 2.4 GHz.



Click here to shop L-com’s Hyperlink brand wireless products.


This Week's Lineup of Bulk Cables

November 21, 2013 at 4:25 PM


If your job or application requires buying cabling in bulk, then you understand that the term “bulk cable” covers a lot of ground. There are several different types of bulk cable, various ways to use them, and multiple avenues to order from.

Bulk CableSpoolAlthough a factory-terminated cable assembly will suit just about any connectivity application, you still want to be mindful of exceptions. Sometimes the connector on a cable is too big to pass through a narrow conduit or too difficult to fish through a wall or a ceiling.  Or the pinning is non-standard, and an off-the-shelf product won't work. Sometimes you won't know the proper length of the cable until you get to your location, so you will be forced to terminate the cable on site. To help you determine what you need, here’s a look at a couple of bulk cable types L-com offers and some ordering advice.


Fiber Optic Cable

fiber cableFiber optic cable is one of the most commonly ordered bulk cable types. Since fiber cable can be run to extreme lengths, it is impossible for anyone to carry factory-terminated cables in all the lengths that may be required.  Also, ordering bulk fiber cable isn’t the same as ordering for standard fiber optic specifications. When ordering fiber optic bulk cable, there are several factors to keep in mind. 

Short fiber cables for patching are generally duplex, with two counts of fiber, or occasionally simplex with one fiber. As you run longer cables or higher counts of cables, it is usually desired to bundle several fibers into a single jacket for convenience and protection when pulling through a conduit.  L-com offers two types of cables bundled in this way: breakout style and distribution style. 

Fiber Distribution cable

The biggest difference between breakout style and distribution style is where the Kevlar strength member is used. In breakout style cables, each internal fiber optic cable has its own Kevlar layer within each jacket.  This can increase the strength of the entire cable and provide additional strength to each fiber if the outer jacket is stripped away for termination.  Usually, due to the thickness of each fiber, breakout style cable has a fewer count of fibers in it compared to distribution style fiber. 


Distribution style cable only has one Kevlar layer around all of the fibers within the outer jacket.  The advantages of this is that the outer diameter of the whole cable is reduced dramatically, so you can fit it in tighter conduits and carry a higher count of fibers in it. The individual fibers are faster and easier to terminate since you don't have to trim back the Kevlar on each fiber cable.


Whichever style works best for you, fiber optic cables are unique in that you do not need to order in specific "put ups" or order lengths. While there is usually a minimum order length, you can order the bulk fiber cable to whatever length you are likely to need.  Note that terminating fiber cables generally requires special training and equipment.


Bulk Ethernet Cabling

Double Shielded: Foil plus Braid - SF/UTP LSZH - 24 AWG Solid Conductor - LSZH Jacket - Category 5E

Often, bulk Ethernet cabling is used in horizontal runs from a server room to individual drop points at workstations.  Because of the sensitivity of the twisted pairs within the cable, it should be spooled carefully in the manufacturer's factory. Once it is pulled off of the spool for use it should not be re-spooled.  For this reason many distributors can only sell the bulk cable at whatever put up it was spooled at originally, which is usually 1,000 feet.  


There is much to know about Ethernet cabling, such as jacket material, shielding and flexibility, but most important is whether the conductors are stranded or solid.  Solid conductors are more popular in horizontal runs because they are much easier to terminate in IDC jacks at the drop points, while stranded conductors are more flexible and best suited for use as patch cables.


There's more...

In addition to the many variations of Fiber Optic and Ethernet bulk cable; there is also bulk cable for USBRG and Low Loss coaxVGA and SVGA  applications and more (all of which L-com carries!).

© L-com, Inc. All Rights Reserved. L-com, Inc., 50 High Street, West Mill, Third Floor, Suite 30, MA 01845