Month: April 2013

A punch down tool is commonly used for the termination works in the copper network. Copper networks are most built by the twisted-pair cables like the Cat5, Cat5e, Cat6 and some newer standard Ethernet cables. These Ethernet cables usually need to be terminated with the keystone jacks, cross-connect blocks or patch panels. The punch down tools can be also called a punchdown tool or a Krone punch down tool, which is a small hand tool used by the telecommunication and network technicians. It is used to terminate the Ethernet cables by inserting the cables wires into the insulation-displacement connectors (IDC) on the punch down blocks, patch panels, keystone modules, and surface mount of boxes.

IDC is a little knife blade with a V-shaped gap or slit between them. In the working process, the punch down tool punches down and force the Ethernet twisted-pair cable conductor into the V-shaped gap. Then the IDC connector makes contact by cutting through, or displacing, the insulations around a single conductor inside a twisted-pair cable.

Most punch down tools are of the impact type, consisting of a handle, an internal spring mechanism, and a removable slotted blade. A punch-down tool is really just a handle with a special blade that fits a particular IDC.

To accommodate different connector types, there are punch down tools with 66, 110, BIX and krone blades. Different blades are used depending on whether you are terminating 110 blocks or 66-blocks. The 66-block is mostly used in cross-connect blocks for voice cross-connects. The 110-block is now generic in usage and is a newer design by AT&T. 110 Block is most used for data network, although it is not absolutely so. Though the blades for each type are pretty different, most punch down tools on the market today can accept both types.

Substitute for a Punch Down Tool
Screwdrivers
The process of punching down a wire properly takes a considerable amount of force. You could just use a small flat-blade screwdriver as a substitute for a punch down tool. It is vital that you should take care no to break the thin wire before it makes contact with the desired slot.

Needle-nose pliers
Needle-nose pliers are also a viable option to replace a punch-down tool for occasional use. If you can find a small electronics set of pliers, it would often include a thin, bent-nose tool that aids in reaching behind challenging angles to push the wire between its slots.

Spring-loaded Nail Sets
A spring-loaded nail set is a standard nail set that incorporates a spring much like a small door spring to allow it to be snapped to generate force in a tight spot. In a time of need, you can grind it down to a flat blade than you can apply a similar force to a jack.

Tool-less Jacks
You can purchase slightly more expensive Ethernet jacks at any home store which utilize a tool-less design. In this design, the eight wires of an Ethernet cable are “grabbed” by a jaw-like interface and snapped and locked shut.

To do to the punching down the with the substitute above can be a good choice when you don’t have a punchdown tool on you hand. Buy it may be hard for an unpracticed man to control the force to the wires with the substitutes. By using the punch down tool helps you in applying the right amount of force in the right direction and assures a firm connection. FiberStore supply 110 punch down tool, Krone punch down tool and many other fiber optic tester and tools with competitive price.

As Fiber to the Home (FTTH) becomes more and more common, the term of fiber optic cable is no longer a strange noun for us. Let review it, a fiber optic cable is a most popular type of network cables that contains strands of glass fibers inside an insulated casing, which is in fact a assembly of optical fibers, the strength members and the cable jacket. Compare with the copper cables, fiber optic cables carry the communication signals by pulses of light rather than the electric. Due to the high capacity and less susceptible to electrical interference, fiber cables are widely used for the fiber optic telecommunication networks.

The optical fiber cables come in many different designs to fit for different environment and application areas. Choosing the right designed fiber cables is essential for your networking jobs.

Loose Tube and Tight Buffer Cables
Loose tuber and tight buffer are two typical designs of the fiber optic cables. Loose tuber fiber cables are used for the outside plant applications, in the Loose Tuber fiber cables, the fibers are placed loosely within a large plastic tube. Usually there are 6-12 fibers placed in the single loose tube. These tubes are filled with a gel or water absorbent powder to protect them from moisture and physical stresses. Loose tube fiber cables are commonly used for underground installations, lashed or self-supporting aerial installations, and other outside plant applications.
Tight Buffer cable designs are used for inside plant application. The fibers inside coated with a buffer coating, with an outside diameter of 900um. Tight buffer cable has two typical constructions with come in breakout design and distribution design.

Ribbon and Aerial Cables
Except for the loose tube and tight buffer cables, there are also ribbon design and aerial design fiber cables. A ribbon cable is a cable with many conducting wires or fibers running parallel to each other on the same flat plane, ribbon cables offer the highest fiber density relative to cable size, maximize use of pathway and spaces, and facilitate ease of termination., which make the ribbon fiber cables the beat choice for deployment in campus, building, and data-center backbone applications where fiber counts more than 24 are required. The ribbon cable can be used in Local area network (LAN) campus and building backbones as well as datacenter backbones.

An aerial cable is an insulated cables usually containing all conductors required for optical transmission system or telecommunication line, which is suspended between utility poles. Aerial cables can be lashed to a messenger or another cable (common in CATV) or have metal or aramid strength members to make them self supporting. Figure 8 self supporting Aerial Cable consists of an optical fiber cable core and integrated stranded steel messenger, used for campus-type environments, aerial links self-support or ducted underground service for long runs between buildings.

According the fiber numbers needed for the fiber optic cables, there are also Single-fiber cables and multi-fiber cables. When selecting a cable design for indoor or outdoor use, it is important that you should know what kind of fiber cable designs that you need. You can have a composite cable including copper conductors for signals or power, contact several professional fiber optic cable OEM manufacturers such as FiberStore. Give them the specification, they will evaluate your requirements and make suggestions for you.

After the installation of fiber optic cabling system, it is needed to test the link transmission characteristics, including several most important test projects like link attenuation characteristics, connector insertion loss, return loss, etc. Following is a brief introduction of the measurements of the key physical parameters during the fiber optic cabling process.

The key physical parameters of fiber optic link：

Attenuation
1. Attenuation is the light power reduction in the fiber optic transmission.
2. Calculation of total attenuation of the fiber optic network: fiber LOSS is the ratio of the Power out of the fiber output end and the Power in of launched into the fiber.
3. The loss is proportional to the length of the fiber, so the total attenuation not only means the loss of fiber itself, but also reflects the length of the fiber.
4. Cable loss factor (α): In order to reflect the characteristics of the fiber attenuation, we introduce the concept of cable loss factor.
5. Attenuation measurements: As the fiber connected to the fiber optic light source and optical power meter will unavoidable take additional losses. Field test must carry on the test reference point setting (zero set). There are several methods for testing the reference point, these methods are mainly based on the link test object selection, in the fiber optic cabling system, since the length of the fiber itself is usually not long, so the test method will pay more attention to the connector and measurement of fiber optic patch cords, the method is more important.

Return Loss
The reflection loss, also known as return loss, refers to the backward reflection light relative to the ratio of the input number of decibels at the fiber optic connector, the return loss is larger the better, in order to reduce the reflection effect of light on the fiber light source and system.

The methods to improve return loss, try to use the fiber end surface is processed into spherical or oblique spherical is an effective way.

Insertion loss
Insertion loss is light signal in the optical fiber after through the connector, the output optical power relative to the input optical power ratio in decibels.
Insertion loss is smaller the better.
The insertion loss measuring method is the same with measuring method of attenuation.

In a word, to complete the measurement of an optical loss, a calibrated optical light source and a standard optical power meter is indispensable.

Prepare the fiber testers you need

1.Use a cable stripper to strip the outside coating of the cable to expose the active wire underneath. Usually, stripping a wire or cable involves scoring the coating to the cable to detach it so it slides away from the outside of the wire without damaging the wire.

2. Generally test every 10 fiber optic connectors need to re-manufacturing optical fiber, each test need to check the fiber If it is damaged.

3. Cut drop the protective layer of the cable as far as possible, instead of with a wire stripper, to reduce the damage of the fiber cable. When use a wire stripper, bent the fiber optical cable 60 degrees in four directions, check the fiber if it is intact. At present, many wire strippers are poor quality, easy to damage the fiber optic, must particularly stressed.

4. The use of imported fiber cleaver, such as Sumitomo FC-6S, complete the pressure optical fiber surface and keep the cutting surface clean, to ensure excellent cutting quality. Excellent cutting surface is flat with the end face of the tilt angle is less than 0.5 degrees and no glitches. Poor Cutting surface the end tilt angle is large and there are glitches. Burr fiber optic inserted into the fiber fast connector may appear broken fiber, fiber butt gap and so on, will leading to a loss of circuit of the products.

The attentions you should mind during the testing process
1. The end surface cleaning first with dust-free paper which is moistened with alcohol, then dry the end surface with dry dust-free paper.

2. Use a combination of fiber light source and optical power meter for testing, prepare the fiber patch cord to the light source, mind the end surface insertion loss less than 0.1dB. The flange test need to use high-quality flanges, the traditional 1-2yuan flange with poor quality, test dozens or hundreds of times, the parameters may deteriorate. Using wire jumper to do the fiber optic cable test, making optical fiber fast connector connected to the fiber under test. Mind the covered wire jumper end surface insertion loss below 0.1dB.

3.Regular cleaning flange ceramic sleeves and special swabs which are covered when test fiber optical connectors, using air-laid paper and ceramic ferrule end face of the fiber jumpers. When suspect flange and fiber jumpers pointer exception, can through the comparative analysis of replace flange and fiber jumpers. General fiber jumpers and flange allows mating cycles of 500 times, need to replace the damaged fiber jumpers and flange timely.

4. When the test index is unnormal, should pay attention to the fiber microbending whether is under the specified range, check the fiber is a broken or existence of a fiber cut.
5. Surface contamination will affect the test parameters, need to prepare the surface detector, check the end cleaning quality when abnormal.

The Method when test data is abnormal

1. Indicators in the 0.3-0.5dB, clean the end surface and retest.
2. Indicators above0.5dB, clean the end surface, re-prepare a test fiber and re-test.

The role of fiber optic connectors is to give a connection or disconnection solution for a fiber optic link. To make the light power from the fiber optic transmitter successfully received by the receiver end, it is required to install the optical fiber connectors at both ends of and optical fiber stand. Install fiber optic connectors is a caution job that you should handle with much carefulness, otherwise there will cause a failure in the optical signals transmission.

The aim of installing fiber optic connectors is to provide a protection for the tripped fiber end in the connector ferrule in case that the cable entering the back of the connector body or prevent the fibers from moving back and fore within the connector body. Good installation will make it free of optical loss and connector or fiber damages.

There are both mechanical methods and chemical methods to fiber optic connector installation, which come in adhesives and polish, cleave and crimp, and fusion splicing the fiber pigtails. Fusion splicing belongs to chemical methods while the last two is for mechanical. Mechanical ways features both cost and time saving, which is suit for small qualities of fiber optic connectors installation, which is also be discussed in the article.

Mechanical Adhesives and Polish
This way can be simply called epoxy and polish, the two main steps indicated. Steps follow, use a Fiber cable stripper to strip the buffer coating and the plastic jacket from the fiber end. Inject the epoxy glue into the connector body until a small amount flows out of the ferrule end. Insert the stripped fiber end into the connector body and then place them into an oven to get heated. After 145j minutes, remove the assembly from the oven for cooling. After the connector is enough cool to handle, use a fiber optic scribe to gently scratch the excess fiber sticking out of the ferrule. Remove the fiber stub and use the finer polishing papers to polish the fibers.

In the reality practice of the fiber connector installations, you will find another type of connectors that already has the epoxy inside the connector body. With this connector type for the job, you can skip the step of injecting the epoxy, and follow the rest steps above to finish the job.

Mechanical Cleave and Crimp
Cleave and crimp is the simplest and the fastest way for the connector installations. Because this method is only for a special type of connector which has already has the polished optical fiber stub installed in the ferrule by the manufacturer. Step for installing these connectors is simple: After the jackets and buffer coating of the fiber cable are stripped by the technician, use a fiber optic cleaver to break off the fiber to within two degrees of 90 degrees at a specific length. Then insert the cleaved fiber end into the back of the connector until it contact the fiber stub within that have been cleaved at the factory, mechanical clamp will be activated automatically. Once the two cleaved fibers ends has holds together, use a crimp tool to crimp the back of connector
to the fiber jacks.

What you should note is that in the whole process of the two mechanical fiber connector installation method, you should make sure all the related tools such as the cable wire strippers, crimping tools, fiber optic cleavers involved should be with high quality. Because a mediocre or poor tool will make the connector poor or inoperative. This article is only about the mechanical method, if you are also interested in the chemical splicing pigtail ways, please pay continuous attention to my blog.