Table of contents

  • What is Communication?

  • Types of Communication

  1. One-way and Two-Way Communication
  2. Analog and Digital Communication
  3. Baseband and Modulated Signal

Wired Type Communication

Coaxial 

  1. Introduction 
  2. Coaxial cable advantages and disadvantages

Ethernet 

  1. Introduction 
  2. History
  3. Ethernet advantages and disadvantages

Optical Fiber

  1. Introduction
  2. Types of Optical Fiber
  3. Advantages and Disadvantages

What is Communication?

Think about communication in your daily life. When you make a phone call, send a text message, or like a post on Facebook, what is the purpose of that activity? Have you ever felt confused by what someone is telling you or argued over a misunderstood email? The underlying issue may very well be a communication deficiency.

  • Source: This is the Origin of the data or information and is responsible for sending data to others.
  • Message: The message is the information or subject matter the source intends to share.
  • Channels: This is the medium by which the source is sending the data or message.
  • Receiver: This is the endpoint of the information to which the data was transmitted.

Types of Communication

Communication is classified in three different ways:

 One-way communication:

One-way communication or simplex communication is the simplest form of communication. In Simplex communication information travels only in one direction. No matter whether the receiver received the signal or not.

Example of One-way or Simplex Communication is TV Broadcasting, RADIO,

and Music. In these all types of Electronic communication, information travels

from source to destination through one-way only.

Two-Way Communication:

Two-Way Communication is further classified into two different ways.

  • Half Duplex
  • Full Duplex

When a person communicates with one another over the telephone, each can transmit and hear information simultaneously, such two-way communication is referred to as Full Duplex Communication.

Full Duplex Communication

An example of Full Duplex Communication is a Telephone, a Two-way radio,

Radar and Sonar etc… Another form of two-way communication is where only one person can transmit or receive information at a time, this type of communication is known as Half Duplex.

In our day-to-day life, we are using any of these but for sake of our subject, we will concentrate on the Full duplex system only. We Can Further divide This type of communication System into Two Parts

Wired Type Communication

  • Wireless Communication

In This Section, We Will Discuss the Wired Type Communication Only

Wired Type Communication is of Many types for eg.

  •  Coaxial
  • Ethernet
  • Optical Fiber

Let us Discuss All of these in one

Coaxial cable

INTRODUCTION: It is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by dielectric insulating material. many coaxial cables also have a protective outer sheath or jacket. The term “coaxial” refers to the inner conductor and the outer shield sharing a geometric axis. Coaxial cable conducts electrical signal using an inner conductor (usually a solid copper, stranded copper, or copper plated steel wire) surrounded by an insulating layer and all enclosed by a shield, typically one to four layers of woven metallic braid and metallic tape. The cable is protected by an outer insulating jacket. Normally, the outside of the shield is kept at ground potential and a signal-carrying voltage is applied to the centre conductor. The advantage of coaxial design is that with differential mode, equal push-pull currents on the inner conductor, and inside of the outer conductor, the signal’s electric and magnetic fields are restricted to the dielectric, with little leakage outside the shield. Further, electric and magnetic fields outside the cable are largely kept from interfering with signals inside the thread, if unequal currents are filtered out at the receiving end of the line. This property makes the coaxial cable a good choice both for carrying weak signals, that cannot tolerate interference from the environment and for stronger electrical signals, that must not be allowed to radiate or couple into adjacent structures or circuits.

What is the transmission speed of a Coaxial Cable?

 The transmission speed of the coaxial cable is 10Mbps (megabits per second), and they offer 80 times more transmission capacity than twisted pair cables.

Coaxial cable advantages and disadvantages

Advantages of coaxial cable:

  •  Inexpensive
  • Easy to wire and install
  •  Easy to expand
  •  Good resistance to EMI
  •  Up to 10Mbps capacity
  •  Durable  

Another benefit of coaxial cable is the electromagnetic field carrying the signal exists only in the space between the inner and outer conductors. This means the coaxial cable can be installed next to metal objects without losing power, unlike other types of transmission lines.

 Disadvantages of coaxial cable:

The main disadvantage of using coaxial cable is that a single cable failure can take down an entire network.

Coaxial cable types:

There are two main types of coaxial cables – ones with an impedance of 75 Ohm (Ω) and ones with an impedance of 50 Ohm.

Cables with 75 Ohm are mostly used for video signals, while 50 Ohm cables tend to be used for data and wireless communications.

In coaxial cables, Ohm refers to the impedance, which is the measure of resistance in the cable to the flow of electrical energy.

Ethernet using Coaxial cable

Introduction

It is a family of computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1983 as IEEE 802.3. Ethernet has since been refined to support higher bit rates, a greater number of nodes, and longer link distances, but retains much backward compatibility. Over time, Ethernet has largely replaced competing wired LAN technologies such as Token Ring, FDDI, and ARCNET.

The original 10BASE5 Ethernet uses coaxial cable as a shared medium, while the newer Ethernet variants use twisted pair and fibre optic links in conjunction with switches. Throughout its history, Ethernet data transfer rates have increased from the original 2.94 megabits per second (Mbit/s) to the latest 400 gigabits per second (Gbit/s). The Ethernet standards comprise several wirings and signalling variants of the OSI physical layer in use with Ethernet.

Systems communicating over Ethernet divide a stream of data into shorter pieces called frames. Each frame contains the source and destination addresses, and error-checking data so that damaged frames can be detected and discarded; most often, higher-layer protocols trigger the retransmission of lost frames. As per the OSI model, Ethernet provides services up to and including the data link layer.

History

Ethernet was developed at Xerox PARC between 1973 and 1974. It was inspired by ALOHAnet, which Robert Metcalfe had studied as part of his PhD dissertation. The idea was first documented in a memo that Metcalfe wrote on May 22, 1973, where he named it after the luminiferous aether once postulated to exist as an “omnipresent, completely-passive medium for the propagation of electromagnetic waves.” In 1975, Xerox filed a patent application listing Metcalfe, David Boggs, Chuck Thacker, and Butler Lampson as inventors. The first standard was published on September 30, 1980, as “The Ethernet, A Local Area Network. Data Link Layer and Physical Layer Specifications”. In February 1980, the Institute of Electrical and Electronics Engineers (IEEE) started project 802 to standardize local area networks (LAN).
Ethernet has evolved to include higher bandwidth, improved medium access control methods, and different physical media. The coaxial cable was replaced with point-to-point links connected by Ethernet repeaters or switches.

What are the benefits of the Ethernet communication protocol?

  • Comparatively low cost
  • All nodes have equal privileges
  •  Ethernet protocol doesn’t need any hubs or switches
  •  It requires little maintenance and administration
  •  More robust to external noise

What are the drawbacks of the Ethernet communication protocol?

  •  Ethernet provides nondeterministic service
  •  It doesn’t give priority to packets
  •  This protocol doesn’t help in a client-server architecture
  • It is not useful in traffic-intensive projects
  •  The receiver doesn’t send any acknowledgement after receiving the packets.
  • Difficult to troubleshoot the problem

Ethernet using Optical Fiber

Introduction

An optical fibre is a flexible, transparent fibre made by drawing glass (silica) or plastic to a diameter slightly thicker than that of human hair. Optical fibres are used most often as a means to transmit light between the two ends of the fibre and find wide usage in fibre-optic communications, where they permit transmission over longer distances and at higher bandwidths (data transfer rates) than electrical cables. Fibres are used instead of metal wires because signals travel along them with less loss; in addition, fibres are immune to electromagnetic interference, a problem from which metal wires suffer. Fibres are also used for illumination and imaging and are often wrapped in bundles so they may be used to carry light into, or images out of confined spaces, as in the case of a fiberscope Specially designed fibres are also used for a variety of other applications, some of them being fibre optic sensors and fibre lasers. Optical fibres typically include a core surrounded by a
transparent cladding material with a lower index of refraction. Light is kept in the core by the phenomenon of total internal reflection which
causes the fibre to act as a waveguide. Fibres that support many propagation paths or transverse modes are called multi-mode fibres, while those that support a single mode are called single-mode fibres (SMF). Multi-mode fibres generally have a wider core diameter and are used for short-distance communication links and for applications where high power must be transmitted. Single-mode fibres are used for most communication links longer than 1,000 meters (3,300 ft).

An optical fibre is a cylindrical dielectric waveguide (nonconducting waveguide) that transmits light along its axis, by the process of total internal reflection. The fibre consists of a core surrounded by a cladding layer, both of which are made of dielectric materials. To confine the optical signal in the core, the refractive index of the core must be greater than that of the cladding. The boundary between the core and cladding may either be abrupt, in step-index fibre or gradual, in graded-index fibre. Light can be fed into optical fibres using lasers or LEDs.

Types of Optical Fiber

The classification of optical fibre can be done based on the materials used, refractive index, & mode of propagation light. The optical fibre cables are classified into two types based on the used materials which include the following.

  •  Plastic optical-fibre cables use polymethyl methacrylate can be used as a core material for light transmission.
  •  Glass fibres include very excellent glass fibres.

The optical fibre cables are classified into two types based on the refractive index which include the following.

  •  A step-index fibre includes a core that is enclosed by the cladding. It includes only a uniform index for refraction.
  •  In graded-index fibres, once the refractive index of the cable reduces, then the radial distance will be increased from the fibre axis. The optical fibre cables are classified into two types based on the mode of propagation light which include the following.
  •  Single-mode fibres are mainly used for transmitting signals over long distances.
  • Multimode fibres are mainly used for transmitting signals over short distances. The four combinations of optical fibres can be formed by the refractive index as well as the mode of propagation which includes step-index single-mode, graded-index single-mode, step-index multimode and graded-index multimode.

The advantages of optical fibre include the following.

  • Bandwidth is higher than in copper cables
  •  Less power loss and allows data transmission for longer distances
  •  The optical cable is resistant to electromagnetic interference
  •  The size of the fibre cable is 4.5 times better than copper wires and
  •  These cables are lighter, thinner, and occupy less area compared with metal wires.
  •  Installation is very easy due to less weight.
  • The optical fibre cable is very hard to tap because they don’t produce electromagnetic energy. These cables are very secure while carrying or transmitting data.
  • A fibre optic cable is very flexible, easily bends, and opposes most acidic elements that hit the copper wire.

The disadvantages of optical fibre include the following

  •  The optical fibre cables are very difficult to merge & there will be a loss of the beam within the cable while scattering.
  •  The Installation of these cables is cost-effective. They are not as robust as the wires. Special test equipment is often required for the optical fibre.
  • Fibre optic cables are compact and highly vulnerable while fitting
  •  These cables are more delicate than copper wires.
  •  Special devices are needed to check the transmission of fibre cables.

The applications of optical fibre mainly involve transmitting the data in the place of metal cables due to the capacity of high transmission and
data transmission. Nowadays, these cables are used for different purposes in a variety of industries like communications, broadcast,
industrial, military, and medical. These cables replace coaxial cables and copper cables. These cables are used in different applications due
to their benefits like high speed and bandwidth.