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12: Cabling - Coaxial & optical fiber cables part 3

Coaxial cable

Coaxial, also referred to as coax, is one of the oldest cables that has been used for data transmission. It has been widely used in LANs in the past. It consists of a single  coated copper wire in the center, an outer mesh made of metal that has two functions which are conducting voltage and reducing outside interference, and an outer jacket made of plastic. Coaxial cable is also used in wireless communication linking antennas to wireless devices. Moreover, the cable is widely utilized for connecting dishes to TV receptor. The following figure reveals the coaxial cable along with its connectors. For more details about coaxial cable, see the previously explained lesson about Ethernet.

Optical fiber cable

Optical fiber is another different type of cable that is also used for data transfer. This cable is characterized by high-speed data transmission with greater bandwidth, that is to say, data is traveled through this cable much faster than either UTP, STP, or Coaxial. That is because fiber optics uses light pulses instead of electrical voltage used by other types of cable. Moreover, this cable is perfectly suitable for long distances, without needing any signal enhancer, especially which are counted by kilometers. Data transmitted through this cable is much securer and safer than the other cables. It is commonly used to link wide area networks such as two networks located in different cities or countries.

Fiber exists in varying types, each one has some features that differ it from the other. Single-Mode and Multi-mode fiber-optic cable are two basic types that are not the same in the way they carry light pulses. The following figure displays the two distinctive types of fiber optics.

As you see in the above figure, in single-mode fiber, light pulses travel in a single straight path, whereas in Multi-mode fiber, light pulses make their way along the cable through multiple paths. Significantly, single-mode fiber can be stretched up to about 100 km, whilst Multi-mode fiber supports shorter distances reaching up to 2 km. They also vary in the light source or the generator of light which can be either Light Emitting Diode (LED) or lasers. Whereas single-mode fiber uses lasers as light source, Multi-mode fiber relies on LEDs as a source of light.

A single core of fiber can carry data only in one direction, and  to carry data in two directions simultaneously, usually a fiber-optic cable with two cores is required. Concerning the health of network installers,  single-mode fiber using lasers is dangerous for the human eye because of the intense of the light to the extent that eyes can be damaged. Thus when installing or troubleshooting such cable, due care is required.

Using this cable in networks needs a large budget on the grounds of the expensive receiving devices, known as photodiodes, as well as the big amount of money that the engineer or technician require in order to install the network because to link a network utilizing fiber optics needs special training.

See the next lesson from here
12: Cabling - Coaxial & optical fiber cables part 3 Reviewed by BOUFTIRA on 8:17:00 AM Rating: 5

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