What Are Some of the Different Fiber Optic Cable Jacket Ratings

There are several parts that make up a fiber optic cable; starting with the core, to the cladding, followed by the coating, the strength member and lastly the outer jacket. The outer jacket is the cover that gives protection and shielding, especially to the optical fibers. Whether it is meant to be indoor/outdoor, UV rated or armored, the jacket is what keeps the fiber protected and useful. Above all of these, the outer jacket is the first layer of protection to the fiber so it can withstand different conditions such as fire, moisture, chemicals, and stress during installations and maneuvering.
The National Electrical Code (NEC) has a classification system for optical fiber cables. The system specifies the requirements regarding how the fiber cables will endure under fire conditions. These requirements concentrate on how these cables can add a dangerous amount of fuel and smoke and transmit fire from one place to another.
Plenum
OFNP – Optical Fiber Non-conductive Plenum – refers to the specific fire code rating of cable that is flame resistant and emits the least toxic fumes or smoke when burned. Plenum rated cables have a higher fire rating and are for both commercial and residential use. They are considered the safest rated cable among jacket types. These cables are primarily used in ducts or pathways for heated and cooled return airflows. These spaces are usually above a ceiling or below a floor that serves as heated or cooled inhabited areas.
Plenum cables are purposely built with a jacket that gives off low amounts of smoke and that is flame retardant. Being able to deter the spread of flames and toxic fumes are the main uses for this jacket rating. The word plenum refers to the space in which air is circulated by a HVAC system. Drop ceilings and raised floors are perfect for the application. Plenum cables still use PVC (Polyvinyl Chloride) in the construction of the plenum jacket but special additives are put into the jacket material in order to make it more flame retardant. The NEC defines plenum cables by the airspace they are put into. Plenum rated cables are often used in building construction, typically they are used as communication cables for the building’s computer and telephone networks. Use of plenum areas for cable does pose some hazard in the event of a fire. This is because there are fewer barriers to contain smoke and flames.
Riser
OFNR – Optical Fiber Non-conductive Riser – is constructed of PVC and will emit toxic fumes when burned. Riser cables are to be run only in non-plenum areas. Plenum can usually replace riser but riser cannot replace plenum. Riser rated cables are typically used in the riser areas of buildings and in vertical telecommunications infrastructures. They connect from one floor to another and are used within shafts in accordance with section 800.53(B) of the NEC (National Electrical Code). They typically have load bearing strength members since they need to be upright without placing added stress on the fiber.
OFNR cable is resistant to oxidation and degradation but still gives off heavy black smoke and toxic gases when it is burned. Yet it is perfectly fine to use as a patch cord or for single in-wall runs. If you want to use it in a building, the building must feature a contained ventilation system and have good fire exits. Location is extremely important for these types of cables.
LSZH – Low Smoke Zero Halogen
These types of cables are made with halogen free materials and although they still emit smoke it is a much safer alternative. This type of cable jacket has superior safety characteristics. This rating offers low smoke, low toxicity and low corrosion standards. Tunnels, enclosed rooms, aircraft, and other minimum-ventilation areas are prime spots for the use of LSZH cables because areas like these are more difficult to escape from quickly. There are many different types of LSZH jacketed fiber optic cables provided for many different uses. The primary use for these types of cables is to satisfy the need for safety and environmental protection. Hospitals, schools and airports are good examples of where these cables should be installed. Due to the amount of people and the serious need for the protection of those people and equipment from toxic matter and gases should a fire ever occur. These cables are especially popular outside the United States, specifically for plenum spaces. Although it may seem as if you can replace plenum with LSZH cables, that’s not really the case. The difference is that while there is a lower smoke rating for LSZH, plenum cables have higher fire spread rating.
Cable tray rated
Tray cables are designed for just that, installation in cable trays. Primarily they are used in industrial control systems, factories, wind turbines and other severe environments. They can be rated for use indoors, outdoors, and in corrosive areas, for hazardous locations or high electrical noise areas. This cable was first introduced in order to combat failures in power and communication applications. There are several different kinds of cables to choose from, these include: Tray Cable (TC), Power Limited Tray Cable (PLTC), Instrumentation Tray Cable (ITC), Exposed Run (ER), and Wind Turbine Tray Cable (WTTC). Effective in direct sunlight as well as underground, these types of cables are extremely versatile in their application. Although cable in tray is viewed as being exposed to a greater risk of mechanical damage and it can be a potential ignition source or fuel load in a fire scenario. Due to this the NEC has a specific requirement in order to ensure the safety and quality of these fiber runs.
When choosing a jacket rating it is important to understand the placement and application where the cables will be run. It is pivotal that the cables meet local code requirements for the installations as well. These ratings are designed to prevent hazards and reduce risks to human and environmental health. We put on a jacket to prevent uncertainties from happening to our body, such as a cold or the flu. Fiber optic cable jacketing is very similar in the sense that we apply a certain compound to prevent a dangerous mishap, or if it does happen in the environment of the application.
Winter is coming… be sure to put on the appropriate jacket! .

Fiber Optic Microscope versus Fiber Optic Video Inspection Probe

Microscopes
If you are new to fiber optics, when you hear the word microscope, you most likely think of the one that was used in science class to look at cells of animals. Well in the fiber optic world, microscopes are a vital tool that should be in all technicians’ tool bags.
An optical microscope is a hand held tool used to look at the end face of a fiber optic connector. What do you look at the end of a connector for you ask? Looking at the end of a connector is vital to making sure that there is nothing wrong with the connector. By looking at the end of a connector you can see if there is any contamination such as dirt or oils, a scratch or even a broken (shattered) ferrule on the connector. Although you look at the whole end face, the primary spot that is looked at is the core of the fiber. The core of the fiber is the vital part, because this is where the light, or your data, will travel. When you are trouble shooting a fiber, visual inspection of the end face of the connector(s) is one of the first steps that should be done – before you pull out your test equipment to shoot with a power meter and light source, or even an optical time domain reflectometer (OTDR).
The very first microscopes that came out were pretty much glorified magnifying glasses. These were the 100X magnification microscopes. They were primarily helpful with multimode fiber connectors due to the core size of multimode fiber being much larger than single mode fiber. The next one to come out was the 200X microscope. These higher powered scopes were needed to better look at the end face and also to view the core of single mode connectors because the size of the core is only 9 microns. They were also used to look at the ends of the multimode connectors more in depth. There are scopes that only use coaxial illumination and ones that illuminate two ways, these being oblique or coaxial illumination. What came out next was the 400x power scope. The 400x scope is the single mode version of what the 200x scope was for multimode. The higher power scope allows you to view the end of a single mode connector in a higher detailed view, which allows you to more closely look at the vital central core of the fiber.
Video Scopes
After microscopes came video scopes. These come in the form of either a hand held probe or bench top scope, and they transfer the image onto some type of monitor. Bench top scopes are typically used in factory (cable assembly houses) or lab (research and development) type settings. A bench top inspection scope is a microscope that is positioned at a work area and that connects to a monitor. It will look at the connector and the image is transported over a connecting wire on to a bigger screen so it is easier to view. There will be better resolution and this makes it easier to focus and see the ferrule end face. These are not easily carried into the field, allowing for a different product known as video inspection probes. These are hand held devices that follow the same concept as the bench top scope, but they are smaller and portable, making them perfect for field use. The video inspection probes can work with several different monitors which makes them flexible for a variety of applications. Some probes come with a small hand held monitor that connects to the probe and allows you to see the end faces. Probes can also be hooked up to different OTDR’s, so while testing your fiber you can also look at the end face of connectors.
Analysis Software
One thing that has always been a problem with microscopes and even video inspection probes when they were first introduced is the fact that you have multiple view points on what is passing and what is failing. This would leave a lot up to human judgment and we all know that one person’s idea of passing may be completely different from another’s. Introduce analysis software that is programmed with industry accepted standards and rules that can look at the end face of the connector and tell you whether or not a connector is passing, or good. Then there is failing which means that the connector may still work but based on the standards it will not be allowed to be used in its current state. This software has a whole system of algorithms built in to it to allow the end face of the connector to be compared to the industry standard or expected parameters in order for a connector to be considered good or bad.
We had a customer that we would make patch cords for and we would test them and send them out to them with everything passing to the standards of testing that are accepted by the industry. The customer would get them in and perform incoming checks on all the patch cords to make sure they were up to their standard. Well after they checked them all, they called us and said that they had rejected 60% of the shipment and needed to send them back. This was a very high amount and we took action and scheduled a visit with the customer. Come to find out, the customer was not using any analysis software so their decision to reject the patch cables was all based on human judgment. We informed them that we use the software that takes the human judgment out of it and instead uses the complex algorithms in the software to help with the decision to pass or fail a connector. Once they learned this, the customer invested in the software and after that we had a zero rejection rate from that customer. By visiting with the customer to evaluate their process and get on the same page for testing purposes, it made it so that the standards being used were the same.
This software has gotten even better throughout the cycle to improve the process of scoping. Scopes now have features that make it easy for a tech to auto focus and auto center the fiber on the monitor or viewing screen. This improves the process of scoping because instead of having to spend time trying to focus and get the end face lined up in the middle of the screen so you can have the software do the pass fail analysis, it now will do this for you and you will know if your connector will pass or fail in a matter of seconds.
Another improvement that has been made takes advantage of the ability of Wi-Fi. There is now a wireless probe that communicates without a cord to get in the way. So now, as long as you are in a location that has a strong Wi-Fi signal, you can use the wireless probe and it will sync to either a tablet or your cell phone or even your OTDR so you can view your connector end faces.

What is the Best Way to Clean Fiber Optic Connectors?

Sometimes it is the simplest of things that cause the biggest problems.
Car won’t start? Check to see if you have gas in the tank. Is your fiber optic network having issues? Do you have performance problems with your fiber optical cable? Check your fiber optic connectors. It can be as simple as dirty connectors. A simple fiber optic connector cleaning can remedy the problem. And no, you do not clean them on your shirt. That doesn’t work. Do they look clean? How can you tell if there is contamination when the fiber optic cable is smaller than a human hair? You can’t.
What are the Differences between a Hand Held Microscope and a Video Microscope?
A digital microscope is just a regular hand held microscope with a camera added to it. Usual magnification ranges from 100x to 800x, a popular magnification is 400x, although 200x can usually do the job. Sometimes a 200x may be a better choice as you can see more of the area that is being inspected. These microscopes can capture images and have documentation software. They provide a report on the inspection. A tech can look at the connector on a computer screen. Some digital microscopes may have a focus, some models have auto focus. All you need do to use this microscope is attach the connector to be inspected and view the results on a computer screen or tablet. This image can also be captured and sent remotely to another location for inspection. A hand held microscope provides basically the same function as the digital microscope but is limited to just the inspection. It cannot be viewed on a computer or tablet screen nor can it transmit the image for remote viewing. However, it will give you the basic information you need on whether or not the connector is dirty.
How Do I Clean a Connector?
Step #1
It is always best to turn off the laser. Never under any circumstances should you look into the end of any optical fiber while it is energized. Looking directly at the fiber can cause irrevocable eye damage.
Step # 2
Remove the protective cap and store it in a clean container. Make sure the container has a cover. This will protect the dust caps from dust or dirt.
Step # 3
The connector now needs a visual inspection with a microscope. Typical dust and debris cannot be seen with the naked eye. A hand held microscope or a video microscope will aid you in seeing the condition of the connector. Take the connector and attach it to either the video microscope or the hand held microscope of your choice. Take a look to see the condition. If you see debris or contamination you need to do some cleaning.
Step # 4
You need to be careful when cleaning or you may introduce more contamination. There are several ways to clean a connector. Wet Cleaning, Wet to Dry Cleaning, and Dry Connector Cleaners.
• Wet Cleaning
• Dry Connector Cleaners
• Wet to Dry Cleaning
Wet Cleaning
You must use reagent-grade 99% isopropyl alcohol and lint free cleaning wipes. The reagent grade alcohol can be purchased in bulk however, it is suggested that you use pre-moistened Isopropyl alcohol wipes as bulk isopropyl alcohol can become contaminated after time and will absorb water from the air. The individually packed wipes will avoid that problem. Dry Connector Cleaners – Also known as click type cleaner or a cassette cleaner are generally used for light contamination. They contain a lint free type of tape designed to clean. It is more difficult to eliminate contaminants using the dry method. Connectors can become electrically charged during this method and may even attract additional contaminants. Use the correct materials to avoid this. Wet to Dry Cleaning – In this process you need to use a small amount of reagent grade alcohol to remove debris and dust particles. Apply a small amount to a lint free fiber optic cleaning cloth. Wipe the connector from the wet area on the cleaning cloth, towards the dry section of the cloth. Do this using a straight across forward motion right across the connector. Never use a figure 8 motion when using this method. This method of moving straight across the lint free surface will remove debris and particles. It is important to note more is not better when using this method. Using too much cleaner could contaminate the surface to be cleaned. Remember, moderate wetness, wipe only straight across from wet to dry.
Always Avoid
• A cleaning process that will leave a residue on the connector or end-face.
• Twisting or pulling on the fiber cable forcefully.
• Looking directly at lasers.
• Touching the area that was cleaned
• Reusing cleaning wipes
• Touching cleaning materials
Conclusion
You always need to inspect your connectors for contamination. Never assume a connector is clean. Connectors in many cases are the source of degradation. Contamination is your systems enemy. Use a microscope to do your inspection. Use a proven procedure and products to clean your connectors. Never trust the quality of your optical signal to guesswork. The only way that you can guarantee that your connectors are doing their job correctly is to; Inspect, clean, inspect.

Why do I need to use fusion splice protection sleeves?

Before we begin to dive into that question let’s get a brief understanding on what a fusion splicer is. If you are in the fiber optic world you will definitely know what a fusion splicer is and most likely will have used one or will be using one. A fusion splicer is a machine that fuses or welds two different pieces of fiber optic glass cables together to become one with an electric current also known as an arc. Most fusion splicers have an attached shrink oven that the protection sleeve is placed into to complete the process. Some splicers do not have an attached shrink oven and an external separate shrink oven will be needed for the application. As mentioned, fiber optic cable is made of glass and glass, especially how thin optical fiber is, will be very brittle and can very easily break. When this fusion of glass is completed, this is where our friend, the fusion protection sleeve steps in.

You may be asking, what is a fusion splice protection sleeve? Well that is a great question! A fusion protection sleeve is used to protect the fusion splice where the two separate pieces of fiber optic cable have been joined into one. A protection sleeve is made up of three parts: An outer shrinkable tube made of heat shrink plastic, an inner tube or fiber tube where the fiber is placed, and a strength member, either made of stainless steel or ceramic, more on this later. The protection sleeve ensures a consistent and reliable means of protection of the fiber when heat is applied from the splicer oven or external oven. Have you ever broke an arm or bone or knew someone who has? When this happens a cast is applied to the broken area. The cast can be interpreted as the protection sleeve and the broken bone area is the fiber optic cable. The cast protects the broken bone as the protection sleeve protects the fused fiber cable.

Fusion protection sleeves can be broken down into basically two categories: single splice protection sleeves and ribbon splice protection sleeves and will most commonly be 40mm or 60mm in length and are normally made of a clear outer tube so you can view the fiber when inside the sleeve for regular inspection and/or maintenance to the cable inside. A single splice protection sleeve is just that, a sleeve that will accommodate a single piece of fused fiber. A ribbon splice sleeve can accommodate multiple fiber splices ranging from 2-12 fibers inside the sleeve. As mentioned above, protection sleeves will either have a stainless steel or ceramic strength member that runs the entire length on the side of the protection sleeve and there is a definitive reason there are two different types of strength members. Fiber optic cable uses light to transmit data and light and glass to not conduct electricity. If a contractor is specifically using fiber optic cable in the application there should be no worry in using a protection sleeve that contains a stainless steel strength member. On the other hand if the fiber optic application will be next to or near any copper/conductive type material, the contractor may consider a splice sleeve that contains the ceramic strength member so there is no electrical disturbance between the copper cable or conductive material and the strength member.

Before the splice sleeve is applied to the fusion splice and the cable, the splice sleeve itself should be inspected before installation. This is done to ensure the sleeve is free from deformity and is clean both on the outside and the inside of the sleeve. The inspection and cleaning process is vital in any fiber optic application ranging from cleaning connector ends to making sure your equipment is clean from any contaminants. Not cleaning your fiber optic accessories and equipment is the leading cause of attenuation in the cable. Attenuation is the measurable loss of signal strength along the cable and it is measured in decibels. Inspecting the inside of the sleeve to make sure it is free of contaminates along with cleaning the fiber before installing the sleeve is a good practice as the slightest bit of contaminates could and most likely will cause attenuation. When not using the sleeves, they should be stored in a clean plastic zip bag for protection during storage.

Aside from the importance of cleaning there are other factors to consider before your splice sleeve installation. As mentioned earlier, protection sleeves are used when fusion splicing. Your fusion splicer has many different settings that can be chosen when splicing and may differ from manufacturer to manufacturer. Fiber tension is one setting that may need to be adjusted in this process. Improper fiber tension can result in an improper or uneven shrink when the protection sleeve is placed in the shrink oven. It is essential to maintain proper tension on the cable and not to twist the fiber when placing in and removing from the oven.

Another factor to consider in this process is actually the type of cable you’re using to splice with. Some fiber optic cables contain a gel similar to petroleum jelly that is contained on the inside jacket of the fiber. This gel will need to be cleaned off of the cable with a special degreaser wipe to ensure the proper fit and finish of the application of the splice sleeve. Inspecting the splice sleeve after it is removed from the heating oven is another good practice as the heat setting may be to high resulting in a split in the sleeve itself or the heat may be to low resulting in an improper shrink to the sleeve. If either of these are observed you may need to adjust the heat setting on the oven itself.

Once all of these installation practices are meet, the protection sleeve along with the attached cable are usually placed in a splice tray. A splice tray is a tray or container that prevents spliced fibers from being damaged or misplaced after splicing. If the cable and protection sleeve will be placed in a splice tray the protection sleeve should have the strength member pointing down, you should not be able to see the strength member when looking at a protection sleeve when it is in a splice tray.

As small as the fusion protection sleeve may be, it is a huge importance to the fusion splicing world of fiber optics. When all of these practices are met, you will be successful when you decide to try your hand at fusion splicing with the added protection of fusion protection sleeves added to your fiber optic cable installation arsenal.

What are the advantages of factory vs. field terminated assemblies?

When looking at terminating fiber optic connectors for a job there are several factors that are taken into account to help decide which way is best. There are field polish connectors in which some form of epoxy (glue) is used to hold the fiber in place. With this one, you have to polish it in the field as well which if you haven’t ever done it, can be very difficult. There are also factory polished style connectors that can be mechanical connectors, pigtails, splice on connectors or pre-terminated cable assemblies. The mechanical connectors have a piece of fiber already in them and you just have to align your field fiber up to the fiber inside the back of the connector. This can be difficult or take some time to master. A fiber pigtail consists of a piece of fiber optic cable that has a connector on one side and no connector on the other side. These can either be fusion spliced to another piece of fiber, or run through conduit and terminated at the other end. The alternate solution would be to have your cable assemblies built to the length that is needed with optical connectors already installed on them in a factory setting. Let’s look at some different qualities to see how this will be beneficial.

Polish Quality
All connectors whether installed in the field or in a factory have to be polished in order to work properly and get the end result of passing a signal over the fiber optic cable. So let’s look at the two different ways to polish. First, you can always hand polish a connector. In this process, you will use a polish puck, rubber durometer pad and a glass plate along with polish film to achieve a suitable connector endface. There are some technicians that have been doing this for a long time and could get close to a perfect polish on the ferrule endface. Not everyone can do a good hand polish. There are several factors that come into play and can cause various results on your finished optical connectors such as the amount of pressure applied while doing your figure 8 on the polish paper. When in a dusty area debris can get on the polish film, causing a connector to be ruined. See how little things in this process can affect the end of the connector and how long it takes to get a good connector? If a connector is bad due to being over polished, pitted or even shattered you will have to repeat the whole process.

On the other hand a factory polish is finished using a polish machine in a manufacturing facility. The amount of pressure is the same. Polish machines have holders that allow many connectors to be polished at once to save time. The procedures used have been honed over time to be the most efficient which helps to produce high quality polishes. In a factory all connectors are checked to a higher standard and are not allowed to be shipped until checked by quality control where they will be scoped and tested. This gives each and every factory connector a perfect outcome.

Plug & Play
When getting factory terminated fiber optic cable assemblies cut to length you are providing yourself with the simple concept of plug and play. This means all you have to do is run your link and then just plug the connectors into your rack, switch or connection point. This not only saves time on your cable installation but also will save you in labor and installation costs. Plug and play is not always a possibility due to restrictions in conduit size or the number of bends that are required to go through. We get that and that is why there are several ways that a connector can be put on a cable. All we are saying is, imagine if you get a house hold item such as a toaster; would you rather take the toaster out of the box, plug it into an outlet and have toast in a matter of minutes? On the opposite side; would you like to get a toaster that does not have a cord and you have to go find all the tools that are needed? Now you have to refresh yourself on how to strip a power cord so you can put a plug on one end. Then you have to open the toaster and get your other end prepped. Point being, we all like to just pull things out of the box, plug them in and away we go.

Pulling Eyes
What is easier than getting a cable that has all the connectors on it and a way to pull it in place? Essentially this is what you have with a pulling eye installed. All a pulling eye is, is a loop that is connected to the Kevlar of a cable assembly. Why the Kevlar? Kevlar, when you have multiple pieces stranded together is not only strong but almost impossible to break. It does not stretch when pulled on and it keeps the fiber cable from stretching. We have had instances when cable has not been pulled by the Kevlar, instead pulling on the jacket of the fiber. The jacket of the cable will stretch and eventually with too much pressure it will break. Also, when a jacket is pulled, when released you get what is called a growing effect of the fiber. Meaning it looks like kids through their growth spurts. The jacket after being released shrinks to try and get back to its original form. When this happens the fibers that are inside will come out the end making it look like your fiber is extending. Not only is this bad for the jacket that protects the fibers but it can also cause breaks in your cable that will not be realized until it is tested. So when pulling fiber cable, always make sure you are pulling correctly using the Kevlar. It’s better to just have a pulling eye installed and save yourself a huge headache.

Higher Overall Quality
When looking at fiber optic connectors there are several factors to consider. Looking above at all the advantages of a factory polish termination along with pulling eyes, you can see how it can save you money and time to go with the factory built cables. Now if you do have to install connectors in the field, the alternative would be to get connectors that are already factory polished such as the ones on a fiber pigtail used when fusion splicing. When doing a job, no one is purposely trying to have bad connectors. Factory polished connectors whether they are pigtails, mechanical connectors or pre-terminated fibers all have the high quality that you will need to show your customer that you take pride in the work you do and want to use the best possible connectors available. Nothing is better than a connector that is polished by a machine, and then put through a rigorous testing phase before they can be considered done and ready.

Fiber Optic Communication Systems: Safe and Reliable Solutions for Mining

What role does fiber optics play in the mining industry?
As technicians and professionals in this business know, the safe and reliable nature of fiber optics makes it the perfect communication solution for use in a wide variety of industries and mining in particular. The anti-spark, strong, fast, and reliable over long distances nature of fiber optic networks, solves many of the inherent problems of using non-fiber optic cables in hazardous situations. However, many in our industry still wonder specifically how is fiber optics used in mining?
HOW IS THE USE OF FIBER OPTICS A PERFECT SOLUTION FOR THE MINING INDUSTRY?
Thanks to lightning fast speeds, quick delivery, and reliable sensing capabilities, fiber optic technology has become an all-seeing and knowing element in underground mine operations. A fiber optic communication system installed in a mine will give real-time, accurate data on all the mining processes. Every second counts when equipment and personnel are below ground. An underground mine’s communication system must be capable of transmitting an error, a signal, or an event immediately over long distances so that safe control of the environment can be maintained.

WHAT DOES REAL-TIME MEAN?
The definition of real-time is “the time in which a physical process under computer study or control occurs.” In essence, real-time means immediately. When a signal is picked up, an event occurs, or a request is submitted it is delivered to the intended operator within milliseconds. If a dangerous situation deep in a mine cannot be handled immediately the worst might be realized.

WHAT IS MEANT BY LONG DISTANCES?
Historically, mining networks used multimode fiber in their communication networks. While multimode fiber can handle a large amount of bandwidth, the large core size of the multimode cable restricts the bandwidth-distance. Where huge networks are required, such as in a large-scale mining operation, multimode cables are of limited use. Additionally, multimode cable systems “have a significantly higher intrinsic light attenuation, or loss of optical power.” Singlemode fiber optic systems offer lower levels of intrinsic attenuation with higher bandwidth distances, creating clear and reliable real-time communications over very long distances. In a mining operation, a very long distance can mean many miles.

HOW DO FIBER OPTICS CREATE SAFETY IN MINING?
Mining is inherently dangerous, so having a responsive communication system is critical. Modern mines have been updated for increased volume output, are dug deeper into the earth, and have a greater focus on safety for all equipment and personnel. Safe and reliable fiber optic networks are the perfect solution for all types of enhanced communication needs in any mining operation.

Why is this true?
• The strands of glass in the fiber optic cable allow for high-speed data transmission with no associated hazards.
• One stray spark could cause a major explosion in a mine. With no electrical conductors in the fiber optic cables, the risk of sparks causing ignition of flammable gases is a non-issue.
• The glass in fiber optic cable eliminates cross-talk and other unwanted transfers of signals making them interference-proof. Clear communication is demanded in any hazardous situation.
• Fiber optic communication networks are designed to preserve the integrity of the system in extremely harsh conditions over extended periods of time. These systems provide safe and reliable vital links between the mine site and the control center.
•Fiber optic networks are immune to electromagnetic interference.

CAN FIBER OPTIC EQUIPMENT MEET STRENGTH REQUIREMENTS?
All elements of a fiber optic network used in mines, from the cable to the connectors, are built to withstand the mechanical strength and survival ability standards required to operate in a harsh underground environment. Fiber optic cables are rated by The Mine Safety and Health Association for:
• Impact and pull strength in installation and continued use.
• Crush resistance from mine tunnel cave-in.
• Extreme swing in temperature effectiveness.
• Protection from moisture and chemical incursion.
• Resistance to vibrations and other sound altering hazards.
• Protection from sparks and flame spread.

DO FIBER OPTICS MEET DEMANDS FOR INCREASED DATA CONVERGENCE?
A mining operation puts huge demands on its network. It must accommodate not only direct communication between personnel but also meet the data transmission demands of other communication features installed in the mine. The elements needed to create an effective control system and environmental monitoring network can only be created with fiber optic cables. In general, the minimum fiber optic system used in mining would include the following.

• A centralized control room that functions as the brains of the mining operation.
• Voice Over Internet Protocol phone and communication system above and below ground.
• A video surveillance system throughout the entire mining operation.
• Sensors to detect environmental hazards including fire and toxic gas buildup.
• A robust emergency communication system.
• Complex conveyor belt system controls.
• Immediate on/off capabilities operated through a remote system.
• Sensor monitoring and feedback.

HOW DOES A MINE EMERGENCY COMMUNICATION SYSTEM WORK?
The fiber optic backbone system has dedicated fibers used only for emergency communications. These fibers are labeled for emergency only in the cross-communication boxes dispersed along the mine shafts. These dedicated fibers go unused until an emergency event occurs. If the emergency requires search teams to enter the mine, the team can use a jumper stored in the boxes to tie the fiber through to the next box. Then they can plug their talk sets to the connectors and communicate with the control room safely and reliably.

In daily operations and for safety and security purposes, fiber optic sensors can be added to the backbone and monitored from a central and often remote location. These proximity sensors are anti-spark and can be attached to safety gates, doors, cabinets, barriers and other access and egress points. In addition to monitoring normal traffic throughout the mine, they are also an early warning system for locating emergencies and shortening response time. Proximity sensors can also be installed and used as call signals identifying the location of an emergency in seconds. Using a latch in the control system, the location is locked on even if the fiber is disturbed after the initial event.

WHAT IS MEANT BY COMPLEX CONVEYOR BELT CONTROL?
The purpose of creating a mine is to get the valued commodity out. A well-designed conveyor system that transports the goods to the surface is the lifeline of the mining operation. A mining conveyor belt system is very complex. It needs to run efficiently and smoothly with little downtime. Modern conveyor belt drive and motor systems are linked with fiber optic cables which offer a problem-free solution for operations.

Mining systems simultaneously perform these and other complex tasks during operations:

• The sequencing of start and stop functions of multiple connected motors.
• Controlling the smooth flow and separation of the mined product.
• Speed sensing for smooth operating control all along the conveyor.
• Correct angles for ascent and descent through the mine tunnels.
• Product weight distribution and load balancing to minimize power consumption.
• Fire and other safety hazard detection on the conveyor belt.

What is presented here is a basic understanding of why fiber optics are the perfect solution for use in any hazardous mining operation. Each mining operation is unique and requires expert analysis to create the ideal system. We know that fiber optics is always the reliable choice for most communication needs.