What are the types of Transmission Media | Guided Unguided

Transmission Media | Guided & Unguided | Beginner Guide

Types of transmission media

·         Guided media

·         Copper Cables

·         Twisted pairs

·         Coaxial cables

·         Uses of Coaxial cables

·         Fibre optic cables

·         Unguided media

·         Networking devices

·         Router

·         Switch

·         Hub

·         Bridge

·         Gateway

·         Repeater

·         NIC (Network Interface Card)

 

A simple definition for Transmission Media - Distribute the signals that carry data and information, from the sender to the receiver.

When data is transmitted from one end to another, it is sent in the form of signals. In order to travel from sender to receiver, signals require a transmission medium of some sort. Therefore, we have various kinds of transmission media. To facilitate a better understanding, we can divide them into two subcategories. 

Types of transmission media

1.       Guided media

Using physical methods to distribute the signals (aka wired transmission media).

This provides a physical pathway for signals to move from their origin to their intended destination. As it uses a physical conductor to transmit signals, it provides a specific direction for these signals. However, it is a well-known fact that these physical conductors come with limitations.

·         Length of the conductor – Each conductor is manufactured up to a specific length. We may need to use multiple conductors for a long distance. It may be necessary to use a repeater in order to cover the entire length.

·         Installation cost – we have to consider an installation cost if we use guided media.

·         Maintenance cost – It is necessary to perform regular maintenance on our belongings to ensure their proper functioning.

 

2.       Unguided media

Using electromagnetic waves to distribute the signals. (aka wireless transmission media).

It doesn’t need a physical medium, signals are transmitted through the form of electromagnetic signals. The signals have no limitations and can be transmitted in all directions. Users who have a device with the necessary capabilities can connect to the network from any location and at any time.

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Number 1 - Guided Media

Guided media can be divided into two parts,

·         Copper Cables

o   Twisted Pair Cables

§  Unshielded Twisted Pair

§  Shielded Twisted Pair

o   Coaxial Cables

§  Thin Coaxial

§  Thick Coaxial

      ·         Fiber Optic Cables

 

Copper Cables

These cables are used to communicate data and information in the technique known as Differential Signalling. In these types of techniques, distribute the data in two complementary signals from two separate wires. The technique is called a Differential pair.

Twisted Pairs

·         Consisting of two copper wires

·         Two copper wires positioned in a spiral pattern

·         Two copper wires covered by PVC

·         Arrangements are the least expensive

·         Mostly used cable pattern    

Twisted pair Cable – A bundle of twisted pairs is wrapped together in a protective cover, which is twisted pair cable. 

Connected by ‘Registered Jack (RJ)’ connectors (RJ 11/ RJ 12/ RJ 45).  

 

Unshielded Twisted Pair (UTP) vs Shielded Twisted Pair (STP)

UTP	STP
High interference	Low interference
Low performance	High performance
Low expensive than STP	More expensive than UTP
	Consists of a metal shield as a cover

Coaxial Cables

These types of cables were used in the past and now, older and obsolete. This also consists of two conductors inside the cable as twisted pair cables.

Plastic cover > Insulator > Outer Conductor > Again insulator > Inner Conductor

Uses of Coaxial Cables

·         Television Antenna cables

·         Long distance telephone transmission

In general, Bayonet Network Connectors (BNC) are used to connect the coaxial cables. But in coaxial based Ethernet networks, T-Connectors and Terminators are used to connect the computer and the cables.

(Hint: Terminator connected to the cable and then the whole item (terminator with cable) connected to the T-connector)

 

Fiber Optic Cables

How it’s made: Several optical fibers, bundle together in a single casing.

Optical fibers are made from glass or plastic material. Signals are distributed as light rays inside the optical fibers. The method by which the light rays are going through the optical fiber is reflection.

Electrical signals are generated by the transmitter, then, those signals are converted into light rays and after that, those light rays are again converted into electrical signals at the receiver.      

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Number 2 - Unguided Media

Unguided media AKA wireless communication distributes electromagnetic signals without having a physical conductor. This technique needs an antenna to transmit signals.

Wireless communication can be divided into 03 categories by the range of frequencies used by each category.

1.       Broadcast radio

2.       Terrestrial microwave

3.       Satellite microwave

 

Broadcast Radio

These waves are used for multicast communications, such as radio and television. 

·         Frequency range 30MHz to 1GHz

·         Includes VHF ranges (VHF consists 30MHz to 300MHz)

·         Includes partial UHF ranges (UHF consists 300MHz to 3GHz)

Terrestrial microwave

Terrestrial microwave transmissions are communicating between two microwave stations on Earth, probably with the help of the Towers. This is the most common method of communicating over long distances.

·         Includes SHF, EHF and the other parts of UHF

·         Directional transmission media

Ex: long distance telephone service, used for both voice and TV transmissions,  

In this scenario, the primary cause of signal loss is attenuation resulting mainly from distance, rainfall, and interference.

Satellite microwave

·         Satellites required remain stable to correct transmission

 

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Networking Devices

What are the networking devices that we use?

§  Router

§  Switch

§  Hub

§  Bridge

§  Gateway

§  Repeater

§  NIC (Network Interface Card)

Router

·         Used to interconnect two or more LANs

Switch

·         Used to interconnect networks

·         Faster than Bridges

·         Has large number of ports

·         Commonly used than bridges

Hub

·         Setup in between the devices

·         Silent device

·         Does not impact signals

Bridge

·         Used to interconnect networks (ex: combining two LANs)

·         Does not pass the data from one network to the other network

·         But if some data assigned for a device on some network, it will pass through the bridge from other network

·         Usually 02 or 03 ports

 

Gateway

·         Used to interconnect two networks that using different protocols to communicate

 

Repeater

·         Setup in between sending and receiving devices

·         Without repeater, Sending signal getting weak at the receiver

·         With repeater, Sending signal strong at the receiver

·         Silent device

·         Does not impact signals

 

NIC (Network Interface Card)

·         NIC placed between network and a computer

·         NIC has two modes, half duplex and full duplex

·         Converting encoded signals into binary data

·         Converting the binary data into encoded signals

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