Informative Guide in Setting up Local Area Network (LAN).

[networkguy]

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basa-basa lang sa ta ani:

http://www.vdvworks.com/UncleTed/PDF/uncleted.pdf

[bayan]

para sa ako pud..regarding ni sa wiring nga discussion..pwde raman nga dili ka mo follow sa standard nga color coding as long as pariha sila end to end..ang color coding for me is just a guide para dili ka mg libog..and dako lang jud nga problema ani kung dili ni ma properly documented..mg libog ang mg sunod sa imong trabaho..

[redfox775]

Fusion Splicing a Fiber Optic Cable

Fusion Splicing

There are several reasons for splicing a fiber cable, these include:

To join two fibers due to a breakage.

To connect some of the cores straight through a patch cabinet.

To extend a cable run.

To reduce losses, a fusion splice has much lower losses than two connectorized cables joined through a coupler.

Or to attach a pre-terminated pigtail.
A Pigtail is a short length of fiber with a factory fitted and polished connector. In the past these were used in preference to field terminations because of the complexities at the time of manually terminating optical fibers. These days pigtails are mainly used where the environment isn't suitable for manual terminations or where speed is a factor.
As with all fiber termination methods, safety is very important so first some safety tips.

* Always work in a clean and tidy area.

* Fiber offcuts are hard to see and can easily penetrate the skin especially if they get into your clothes, so care must be taken to ensure the safe disposal of all offcuts. Dispose of fiber scraps immediately using a suitable container and do not throw into a waste paper bin. * Because of the dangers of ingesting a fiber, do not eat or drink in the termination area.

* Fusion splicers use an electric arc to fuse the fibers together so they should never be used in an environment where flammable gases or liquids are present.* Never look into the end of a live fiber connector. Holding some multimode fibers up to a piece of paper may prove the presence of light and therefore prove that it is live, but it doesn't prove that it isn't live! Some laser powered equipment use light which is outside of the visible spectrum, so err on the side of caution.

Overview A fusion splice is a way of joining two fiber cores by melting the ends together using an electric arc. A splicing machine is used because an extremely high degree of accuracy is needed, the machine first has to align the cores and then apply the exact amount of heat to melt the ends before pressing them together.
Splicing can be carried out using a mechanical splice but these only hold the fiber ends together, precisely aligned but not permanently joined.
There are four basic steps to fusion splicing

1 - Strip back all coatings down to the bare fibers and clean using isopropyl alcohol.
2 - Cleave the fibers using a precision cleaving tool and put the heat shrink tube on to one of the ends.
3 - Fuse the fibers together in the fusion splicer.
4 - Put the heat shrink protector on the fiber joint.

Fusion Splicing Method

Stripping
Strip back the external sheathing of the cable using a rotary stripping tool. Cut back the aramid strength member using ceramic or kevlar scissors.
Strip the primary buffer from the fiber using fiber strippers not ordinary wire strippers. Do this a small section at a time to prevent the fiber breaking, about 10mm (3/8 in) on each cut is fine until you get used to it. Strip back about 35mm (1.5 in).
Clean the bare fiber with a lint free wipe and isopropyl alcohol, it will "squeak" when it is clean.

Cleaving
The cleaver first scores the fiber and then pulls the fiber apart to make a clean break. It is important that the the ends are smooth and perpendicular to get a good joint, this is why a hand held cleaver will not do.

Cleavers vary from manufacturer to manufacturer and you should read the instructions for the one you are using. Basically the operation consists of putting the fiber into the groove and clamping, then close the lid and press the lever. Easy eh!
Good cleaving tools can cost between $800 to $3000
The Fusion Process
Once the fiber ends are prepared they are placed in the fusion splicer. Press the button and the machine takes care of the rest of the fusion process automatically.

First the two fibers are aligned, you can see this on the photo where a much magnified image shows the two fiber ends. The display also shows how well the cleaver does its job of producing a perfect 90 degree cut.

If you watch very carefully in the video you can see the X and Y alignment that takes place. The splicer aligns the fibers on one axis and then from another camera angle set at at 90 degrees, it aligns the other axis. This high precision alignment is critical for a low loss joint, any mismatch of the fiber cores will significantly reduce the propagation of light through the joint.

Bearing in mind that we are dealing with two very small glass rods of only 125 microns in diameter, it brings it home as to how extremely accurate these machines are.
Once the fibers are aligned the splicer fires an electric arc between the two ends which melts them immediately and pushes them together, or fuses them into one piece of fiber.
The fusion splicer then tests for dB loss and tensile strength before giving the "OK" beeps for you to remove the splice from the machine.


Protection
The splicer in the video has a built in heat shrink oven, so when the fiber is taken out of the machine the protective tube is slid into place and the whole assembly is put into the oven to shrink the tube on to the splice.

The protective tube gives physical protection to the splice and further protection is provided by placing the splice into a splice tray.
Once all of the fibers have been joined the whole tray is then fixed into a splice box which protects the cable joint as a whole and the cable clamps are then tightened to prevent any external forces from pulling on the splices.

Fusion splicers are expensive and can cost between about $5,000 to over $30,000, so you need to be doing a lot of splicing to justify the initial outlay but, for a low loss and relatively fast connection it is the only tool for the job.

[redfox775]

Fibre Optics

The installation and termination of optical fibers used to be regarded as somewhat of a 'Black Art' but with standardization and easier terminating techniques this is no longer true. A basic knowledge of the subject, together with a quick lesson and some practice can get you started in fibre optics, but to really understand the subject and gain full in-depth knowledge will require some formal training.

There are lots of Fibre Optic training companies offering recognised qualifications and a quick search on the net should find one in your area.
If you are in the UK, Optical Technology Training Ltd offer several different courses to choose from including a City & Guilds qualification.

There are also hundreds of books on fibre optics and a search on the Barnes and Noble web site will find nearly 600 titles. Without reviewing them all it is difficult to know what to recommend, but two of the best sellers in this category seem to follow on quite nicely from this page without getting too involved with mathematics. The two books are the Introduction to Fibre-Optics by John Crisp and Understanding Fiber Optics, Third Edition by Jeff Hecht.

Right, lets get on with the lesson

First a bit history
In 1870, John Tyndall demonstrated that light follows the curve of a stream of water pouring from a container, it was this simple principle that led to the study and development of applications for this phenomenon. John Logie Baird patented a method of transmitting light in a glass rod for use in an early colour TV, but the optical losses inherent in the materials at the time made it impractical to use. In the 1950's more research and development into the transmission of visible images through optical fibres led to some success in the medical world, as they began using them in remote illumination and viewing instruments. In 1966 Charles Kao and George Hockham proposed the transmission of information over glass fibre, and they also realised that to make it a practical proposition, much lower losses in the cables were essential. This was the driving force behind the developments to improve the optical losses in fibre manufacturing, and today optical losses are significantly lower than the original target set out by Charles Kao and George Hockham.


The advantages of using fibre optics
Because of the Low loss, high bandwidth properties of fiber cable they can be used over greater distances than copper cables, in data networks this can be as much as 2km without the use of repeaters. Their light weight and small size also make them ideal for applications where running copper cables would be impractical, and by using multiplexors one fibre could replace hundreds of copper cables. This is pretty impressive for a tiny glass filament, but the real benefits in the data industry are its immunity to Electro Magnetic Interference (EMI), and the fact that glass is not an electrical conductor. Because fibre is non-conductive, it can be used where electrical isolation is needed, for instance between buildings where copper cables would require cross bonding to eliminate differences in earth potentials. Fibres also pose no threat in dangerous environments such as chemical plants where a spark could trigger an explosion. Last but not least is the security aspect, it is very, very difficult to tap into a fibre cable to read the data signals.


Fibre construction
There are many different types of fiber cable, but for the purposes of this explanation we will deal with one of the most common types, 62.5/125 micron loose tube. The numbers represent the diameters of the fibre core and cladding, these are measured in microns which are millionths of a metre. Loose tube fibre cable can be indoor or outdoor, or both, the outdoor cables usually have the tube filled with gel to act as a moisture barrier which stops the ingress of water. The number of cores in one cable can be anywhere from 4 to 144 Over the years a variety of core sizes have been produced but these days there are only three main sizes that are used in data communications, these are 50/125, 62.5/125 and 8.3/125. The 50/125 and 62.5/125 micron multi-mode cables are the most widely used in data networks, although recently the 62.5 has become the more popular choice. This is rather unfortunate, because the 50/125 has been found to be the better option for Gigabit Ethernet applications.
The 8.3/125 micron is a single mode cable which until now hasn't been widely used in data networking, this was due to the high cost of single mode hardware. Things are beginning to change because the length limits for Gigabit Ethernet over 62.5/125 fibre has been reduced to around 220m, and now, using 8.3/125 may be the only choice for some campus size networks. Hopefully, this shift to single mode may start to bring the costs down.


What's the difference between single-mode and multi-mode?
With copper cables larger size means less resistance and therefore more current, but with fibre the opposite is true. To explain this we first need to understand how the light propagates within the fibre core.




Light propagation
Light travels along a fiber cable by a process called 'Total Internal Reflection' (TIR), this is made possible by using two types of glass which have different refractive indexes. The inner core has a high refractive index and the outer cladding has a low index. This is the same principle as the reflection you see when you look into a pond. The water in the pond has a higher refractive index than the air, and if you look at it from a shallow angle you will see a reflection of the surrounding area, however, if you look straight down at the water you can see the bottom of the pond. At some specific angle between these two view points the light stops reflecting off the surface of the water and passes through the air/water interface allowing you to see the bottom of the pond. In multi-mode fibres, as the name suggests, there are multiple modes of propagation for the rays of light. These range from low order modes which take the most direct route straight down the middle, to high order modes which take the longest route as they bounce from one side to the other all the way down the fibre.
This has the effect of scattering the signal because the rays from one pulse of light, arrive at the far end at different times, this is known as



Intermodal Dispersion (sometimes referred to as Differential Mode Delay, DMD). To ease the problem, graded index fibres were developed. Unlike the examples above which have a definite barrier between core and cladding, these have a high refractive index at the centre which gradually reduces to a low refractive index at the circumference. This slows down the lower order modes allowing the rays to arrive at the far end closer together, thereby reducing intermodal dispersion and improving the shape of the signal.

[netcommando]

hahay... napugos jud kog basa sa notes ug mao ni ako nakita...
My last input for the day before duty... he he he

A cable can sometimes be incorrectly wired with correct continuity, but not with correct pairing. This often happens when the cable is terminated consistently at both ends but in the wrong order. A dynamic or AC test is required to detect this type of error. If the cable has correct continuity but a pairing error, crosstalk will likely occur. Crosstalk is the bleeding of signals carried by one pair of conductors onto another pair through the electrical process of induction. The conductors do not need to make contact with each other as the crosstalk is transferred magnetically. This is an unwanted effect that can cause slow transfer or completely inhibit the transfer of data signals over a long cable segment. The wire twists found in Cat5e cable significantly reduce crosstalk and its side effects.

Electro Magnetic Interference (EMI) is an unwanted signal that is induced into the cable. Unlike crosstalk, EMI is typically induced from a source that is external to the cable. This could be an electrical power cable or device, or in some cases adjacent Cat5e cables that do not adhere to the 568A and 568B standards. Attenuation is the loss of signal in a cable segment due to the resistance of the wire plus other electrical factors that cause additional resistance. Longer cable length, poor connections, bad insulation, high levels of crosstalk, and EMI will all increase the total level of attenuation. The 568A and 568B standards were developed to provide more effective communications for longer distances in a Cat5e cable segment than using non-standard schemes. Fiber Optic cable is the only medium that is completely immune to crosstalk and EMI since it uses light to transfer data instead of electrical current.

Therefore, not following the standards will have effects... dili kay wala lang.

[networkguy]

hahay... napugos jud kog basa sa notes ug mao ni ako nakita...
My last input for the day before duty... he he he

A cable can sometimes be incorrectly wired with correct continuity, but not with correct pairing. This often happens when the cable is terminated consistently at both ends but in the wrong order. A dynamic or AC test is required to detect this type of error. If the cable has correct continuity but a pairing error, crosstalk will likely occur. Crosstalk is the bleeding of signals carried by one pair of conductors onto another pair through the electrical process of induction. The conductors do not need to make contact with each other as the crosstalk is transferred magnetically. This is an unwanted effect that can cause slow transfer or completely inhibit the transfer of data signals over a long cable segment. The wire twists found in Cat5e cable significantly reduce crosstalk and its side effects.

Electro Magnetic Interference (EMI) is an unwanted signal that is induced into the cable. Unlike crosstalk, EMI is typically induced from a source that is external to the cable. This could be an electrical power cable or device, or in some cases adjacent Cat5e cables that do not adhere to the 568A and 568B standards. Attenuation is the loss of signal in a cable segment due to the resistance of the wire plus other electrical factors that cause additional resistance. Longer cable length, poor connections, bad insulation, high levels of crosstalk, and EMI will all increase the total level of attenuation. The 568A and 568B standards were developed to provide more effective communications for longer distances in a Cat5e cable segment than using non-standard schemes. Fiber Optic cable is the only medium that is completely immune to crosstalk and EMI since it uses light to transfer data instead of electrical current.

Therefore, not following the standards will have effects... dili kay wala lang.

hahaha napugos jud ka, bro? bitaw ma challenge man sad gud ka labi na mga professionals mo question nimo, pero it's a good learn for all of us. basta remember lang jud, bro, "maski unsa pa ka maayong laki sa usa ka tao naa pa jud molabaw niya og dili tanan nahibaw-an sad niya".

[wire]

hahay... napugos jud kog basa sa notes ug mao ni ako nakita...
My last input for the day before duty... he he he

A cable can sometimes be incorrectly wired with correct continuity, but not with correct pairing. This often happens when the cable is terminated consistently at both ends but in the wrong order. A dynamic or AC test is required to detect this type of error. If the cable has correct continuity but a pairing error, crosstalk will likely occur. Crosstalk is the bleeding of signals carried by one pair of conductors onto another pair through the electrical process of induction. The conductors do not need to make contact with each other as the crosstalk is transferred magnetically. This is an unwanted effect that can cause slow transfer or completely inhibit the transfer of data signals over a long cable segment. The wire twists found in Cat5e cable significantly reduce crosstalk and its side effects.

Electro Magnetic Interference (EMI) is an unwanted signal that is induced into the cable. Unlike crosstalk, EMI is typically induced from a source that is external to the cable. This could be an electrical power cable or device, or in some cases adjacent Cat5e cables that do not adhere to the 568A and 568B standards. Attenuation is the loss of signal in a cable segment due to the resistance of the wire plus other electrical factors that cause additional resistance. Longer cable length, poor connections, bad insulation, high levels of crosstalk, and EMI will all increase the total level of attenuation. The 568A and 568B standards were developed to provide more effective communications for longer distances in a Cat5e cable segment than using non-standard schemes. Fiber Optic cable is the only medium that is completely immune to crosstalk and EMI since it uses light to transfer data instead of electrical current.

Therefore, not following the standards will have effects... dili kay wala lang.

...naa ra man lagi na bro...
...the longer the cable the higher the resistance sa copper and it does affect the signal traverse from one end to the other regardless of the Schemes being discussed, however, sometimes the tendency why the non-standard schemes is being discouraged because, a cable can be wired with correct continuity, but not with correct pairing. This often happens when the cable is terminated consistently at both ends, but in the wrong order. A dynamic or AC test is required to detect this type of error. If the only error is a split pair error, the cable has correct continuity and will likely cause crosstalk.
Crosstalk is the bleeding of signals carried by one pair of conductors, onto another pair
through the electrical process of induction. The conductors do not need to make contact with eachother
as the crosstalk is transferred magnetically. This is an unwanted effect that can cause slow transfer or
completely inhibit the transfer of data signals over a long cable segment. The purpose of the wire twists
found in Cat5e cable is to significantly reduce the crosstalk and its side effects.

[dammy]

hey guys drink some beer and relax... we already learn basics.

as long as it works that is fine but when time comes failure arises be sure to have a conclusive evidence and stand for it and be sure your on the right track. i guess you people are the one responsible for our communications here in cebu, do the best you can for our community.

the network enthusiast level here are awesome be a model for everyone. thank you...

i dont have time to read all your comments here but it sure have knowledge to get from here.

[netcommando]

i hope things are clearer now... good morning istoryans.

[ate_flo2]

thanks to all the input guys