What is a network?

A network is a collection of devices connected by communication links. A device can be a computer or any instrument capable of sending and receiving data or information formed by other nodes toward the network. A channel that connects people or things is known as a network. It sends the data from one place to another. It is the basic concept of a computer, network, and data communications.

Network transmission achieved via cabling

Every communication is possible by cabling, and a cable acts as a medium between transmission and reception of information and data. A medium can remain as guided and unguided. Guided media is recognized as wired and unguided media is considered wireless. There are different types of cabling of lower data rate to the higher data rate in networking transmission. The lower data rate cabling is a twisted pair and coaxial cable. The higher data rates cabling is fiber optic cable. Cabling provides the path for the transmission process.

Classes of transmission media

Transmission media- A transmission media is defined as anything that can carry information or data from a sender to receiver. As a transmission medium for two people having a conversation is the air, which acts as a medium to convey the information as a signal.

Guided media

This provides a channel from one device to another by using twisted pair cable, coaxial cable, and optical fiber cable. A twisted pair and coaxial cable made up of copper conductors (copper wire); accepts and carries signals in the pattern of electrical current. Optical fiber cable accepts and carries signals in the form of light.

The twisted pair (Pair Cable)- It has two conductors (generally copper), each including plastic insulation and twisted together. One wire is used to transfer the signals to the destination, and the other wire is used only as ground. The interference and crosstalk can affect pair of wires when signal transmitted by source changes and create unwanted noisy signals. If two wires are identical, the outcome from these wires is undesired signals, and they are not equivalent in both wires because they are at distinct places. This creates noise or crosstalk sources. It can give result in separation at the destination. By doing the twisting of wires, an equivalence is maintained. They are of two types namely Unshielded Twisted Pair (UTP) and Shielded Twisted Pair (STP).

Unshielded Twisted Pair (UTP) cable

It is the  simple twisted-pair cable used for communications. It is used to transmit data in small regional areas. RJ-45 connector is used to connect the UTP cables. Unshielded twisted pair (UTP) is further divided into seven divisions based on the quality of the cable. The division is made with regards of TIA/EIA 568 standard.

The divisions are named as

• CATEGORY 1
• CATEGORY 1
• CATEGORT 2
• CATEGORY 3
• CATEGORY 4
• CATEGORY 5
• CATEGORY 5e
• CATEGORY 6

Shielded Twisted-Pair (STP) cable

IBM has additionally created a variant of twisted-pair cable, which is called a Shielded Twisted-Pair (STP). STP cables are metal foil or mesh shielding that encases each of them, and is insulated as a conductor. The metal casing or a copper wire enhances the variety of cable by limiting the penetration of unwanted noise or crosstalk. It is heavier and greatly expensive. STP cable is similar as to UTP cable.

Coaxial cables

Coaxial carries higher frequency signals than twisted-pair cable. Coaxial cable is also recognized as coax, which carries signals of higher frequency scales than the twisted-pair cable. Coaxial having two wires, first one has a central core conductor of solid or stranded wire, generally copper enclosed (copper cable) in an insulating sheath, which is in aid and encased in an outer conductor of element foil, rope, or maybe a combination of the two. The external hard wrapping serves as a shield against unwanted noise and second conductor, which creates the whole circuit. Outer conductor is also enclosed with an insulating cover, and the entire cable is shielded by a plastic cover

These cables are utilized in TVs, Ethernet, and thick Ethernet. It has a T-connector, which is used to connect three cables. There are different categories of co-axial RG-59, also (RG-6) of 75-ohm impedance, which is used for cable TV, RG-58 of 50-ohm impedance, and for the Thin Ethernet; whereas, RG-ll of 50-ohms is used for thick Ethernet. Coaxial has a full duplex instead of a half-duplex.

Fiber-optic cable

Fiber optic cable used for higher data rate, longer signal distance with minimum interference. Optical fiber cable is made up of glass or plastic and conveys signals in the form of light. To understand the working of fiber optic cable, first explore several characters of the light. Light progresses in an even line, as it moves into a single consistent substance. If a ray of light progressing within one substance abruptly enters a different substance, the ray shifts the direction of light. Transmissions of light in fiber optical cable is based on the principle of total internal reflection.

Its circuitry has a transducer, optical source, optical channel, optical detector, and electrical receiver. where transducer converts information from source to an electrical signal. An optical source can be laser or LED. An optical channel is a fiber optic cable; detectors convert the optical signal into an electrical signal, and the detector can be an avalanche photo diode. The Refractive index in core diameter is always higher than cladding, also has signal-to-noise ratio is low. It has two modes.

Multimode fiber is nominated because multiple beams of light source move within the core at different paths. So how these beams move inside the cable, completely depends upon the construction of the core. In the multi-mode step-index, the fiber thickness of the core is constant from the center to the corners. A beam of light moves within this fixed density in a uniform line until it reaches an electrical interference of the core and cladding. The term step-index introduces the sudden change, which provides the distortion of the signal as it passes by the fiber. So, the second type of fiber is known as a multimode graded-index fiber, which decreases this distortion of the signal within a cable. Single-mode utilizes step-index fiber with a highly directed source of light that confines the beams to a small range of angles, all close to the horizontal.

Unguided media

It conveys electromagnetic waves externally utilizing a material conductor. This type of communication is also known as wireless communication. Signals are generally transmitted via free space and are available to anyone whose device has the capability of receiving them. 

Free Space- Free space communication is wireless communication made where the wired communication fails. This communication is made for satellite communication and mobile communication either it can be said that it is done in high-rate data transmission.

Context and application

This topic is significant in the professional exams for Undergraduate, Graduate, and Post-Graduate courses.

• Bachelors in network communication
• Bachelors in computer science
• Masters in computer science

Practice problems

Question 1) Which of the following belongs to unguided media?
a) Coaxial cable
b) Fiber-optic cable
c) Free space
d) Twisted pair
Answer: Option c

Explanation- Unguided media are considered for wireless communication.

Question 2) Which cable is used for voice and data communication?
a) Coaxial cable
b) Fiber-optic cable
c) shielded cables
d) Twisted pair
Answer- Option d

Explanation- Twisted pair cable is used for data and voice communication

Question 3) Which cable carries data signals in the form of light?
a) Coaxial cables
b) Fiber-optic cable
c) Copper cables
d) Twisted pair
Answer- Option b

Explanation- Fiber optic cable is based on the principle of total internal reflection.

Question 4) On which principle is the fiber-optic cable based?
a) Total internal reflection
b) Frequency modulation
c) Phase modulation
d) None
Answer- Option a

Explanation- Fiber optic cable is based on the principle of total internal reflection.

Question 5) Which of the following is the fiber optic signal?
a) Radio wave
b) Lightwave
c) Infrared wave
d) None
Answer- Option b

Explanation- Fiber optic cable signal is a light wave.

Common Mistakes

• Wired cables are for limited distances
• Wireless networking are more affected by noise
• Failing to control environment
• Fail to test your network

Related Concepts

• Medium of transmission
• High data rate
• Low data rate
• Network device connection
• Network interconnection/internet