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TRANSMISSION MEDIA

7 min read

  • WHAT IS DATA COMMUNICATION?
    • [[#WHAT IS DATA COMMUNICATION?#Data Communication System components|Data Communication System components]]
    • message, sender, receiver, transmission media, protocol
  • DATA TRANSMISSION
    • [[#DATA TRANSMISSION#WHAT IS DATA TRANSMISSION?|WHAT IS DATA TRANSMISSION?]]
    • [[#DATA TRANSMISSION#1. SIMPLEX|1. SIMPLEX]]
    • [[#DATA TRANSMISSION#2. HALF-DUPLEX|2. HALF-DUPLEX]]
    • [[#DATA TRANSMISSION#3. FULL-DUPLEX|3. FULL-DUPLEX]]
  • TYPES OF TRANSMISSION MEDIA
    • [[#TYPES OF TRANSMISSION MEDIA#1. GUIDED MEDIA|1. GUIDED MEDIA]]
      • [[#1. GUIDED MEDIA#TYPES OF GUIDED MEDIA|TYPES OF GUIDED MEDIA]]
    • [[#TYPES OF TRANSMISSION MEDIA#1. TWISTED PAIR CABLE|1. TWISTED PAIR CABLE]]
      • [[#1. TWISTED PAIR CABLE#1. SHIELDED TWISTED|1. SHIELDED TWISTED]]
      • [[#1. TWISTED PAIR CABLE#2. UNSHIELDED TWISTED PAIR|2. UNSHIELDED TWISTED PAIR]]

WHAT IS DATA COMMUNICATION?

  1. Data Communication is defined as exchange of data between two devices via some form of transmission media such as a cable, wire or it can be air or vacuum also.
  2. Data Communication refers to the sharing or transfer of collection of facts, figures, etc.
  3. For data communication, communicating devices must be a part of communication system made up of a combination of hardware or software devices and programs.
  4. Computer communications : A process in which two or more computers or devices transfer data, instructions, and information.

Data Communication System components

  1. There are mainly five components of a data communication system:
    1. Message
      1. the information to be exchanged between two points.
      2. texts, numbers, pictures, audio, and videos.
    2. Sender
      1. It is the node (device) that is intended to send the data
      2. It has mechanisms of its own that make data encoded in a format that is feasible and secure to transfer on the transmission medium accurately and timely.
      3. It is simply a device that sends data messages. It can be a computer, mobile, telephone, laptop, video camera, or workstation, etc.
    3. Receiver
      1. receiving the encoded information
      2. decoding it into a certain format accurately
      3. sending the feedback is the receiver.
      4. It is a device that receives messages. It can be a computer, telephone mobile, workstation, etc
    4. Transmission Medium
      1. It is a path such as a cable
      2. that serves as traveling media on which the message is transferred from the sender to the receiver end.
    5. Set of Rules (Protocols)
      1. The protocol is the rules that are agreed upon between sender and receiver
      2. Which govern the entire exchange process.
      3. These protocols make communication possible between two devices without them may be connected but won’t be communicating.

DATA TRANSMISSION

WHAT IS DATA TRANSMISSION?

  1. Data transmission is sending and receiving of digital or analog data between devices.

  2. This can be achieved through different mediums, such as cables, optical fibers, or wireless signals.

  3. Data Transmission mode defines the direction of the flow of information between two communication devices.

  4. AKA Data Communication/Directional/Transmission Mode.

  5. It specifies the direction of data flow from one place to another in a computer network.

  6. Each communication channel has a direction associated with it, and transmission media provide the direction. THUS, direction mode

  7. Data Transmission mode is divided into three categories:

    1. Simplex
    2. Half-Duplex
    3. Full Duplex

1. SIMPLEX

  1. Simplex is the data transmission mode in which the data can flow only in one direction.
  2. the communication is unidirectional.
  3. a sender can only send data but can not receive it.
  4. receiver can only receive data but can not send it.
  5. This transmission mode is not so popular because we cannot perform two-way communication between the sender and receiver in this mode.
  6. It is mainly used in the business field as in sales that do not require any corresponding reply.
  7. It is similar to a one-way street.
  8. For Example, Radio and TV transmission, keyboard, mouse, etc.

2. HALF-DUPLEX

  1. data can flow in both directions, but in one direction at a time.
  2. AKA semi-duplex
  3. each station can both transit and receive data but not simultaneously.
  4. when one end is sending data the other can only receive.
  5. entire capacity of the channel can be utilized for each direction.
  6. Transmission lines can carry data in both directions, but the data can be sent only in one direction at a time.
  7. This type of data transmission mode can be used in cases where there is no need for communication in both directions at the same time.
  8. For Example, Walkie-Talkie, Internet Browsers, chatrooms etc.

3. FULL-DUPLEX

  1. Full-Duplex is the data transmission mode in which the data can flow in both directions at the same time.
  2. It is bi-directional in nature.
  3. It is two-way communication in which both the stations can transmit and receive the data simultaneously.
  4. Full-Duplex mode has double bandwidth as compared to the half-duplex.
  5. The capacity of the channel is divided between the two directions of communication.
  6. This mode is used when communication in both directions is required simultaneously.
  7. For Example, a Telephone Network, in which both the persons can talk and listen to each other simultaneously

TYPES OF TRANSMISSION MEDIA

  1. In data communication terminology, a transmission medium is a physical path between the transmitter and the receiver.
  2. It is the channel through which data is sent from one place to another.
  3. Transmission media, also known as communication channels, are the physical pathways through which data is transmitted from one location to another in a communication system.
  4. There are two main types of transmission media in computer networks.
    1. GUIDED
      1. guided media requires physical medium
    2. UNGUIDED
      1. unguided media requires air for communication.

1. GUIDED MEDIA

  1. It is defined as the physical medium through which the signals are transmitted.
  2. It is also referred to as Wired or Bounded transmission media.
  3. Signals being transmitted are directed and confined in a narrow pathway by using physical links.
  4. Features:
    1. High Speed
    2. Secure
    3. Used for comparatively shorter distances

TYPES OF GUIDED MEDIA

Types Of Guided media:

  1. Twisted Pair Cable
  2. Coaxial Cable
  3. Optical Fiber Cable

1. TWISTED PAIR CABLE

  1. It consists of 2 separately insulated conductor wires wound about each other.
  2. Generally, several such pairs are bundled together in a protective sheath.
  3. Twisted pair is a physical media made up of a pair of cables twisted with each other.
  4. They are the most widely used Transmission Media.
  5. A twisted pair cable is cheap as compared to other transmission media.
  6. easy Installation, and it is a lightweight cable.
  7. Twisted Pair is of two types:
    1. Shielded Twisted Pair
    2. Unshielded Twisted Pair

1. SHIELDED TWISTED

  1. This type of cable consists of a special jacket (a copper braid covering or a foil shield)
  2. block external interference.
  3. It is used in fast-data-rate Ethernet and in voice and data channels of telephone lines.
  4. Better performance at a higher data rate than Unshielded.
  5. It Eliminates crosstalk
  6. Comparatively faster

2. UNSHIELDED TWISTED PAIR

  1. UTP consists of two insulated copper wires twisted around one another.
  2. An unshielded twisted pair is widely used in telecommunication.
  3. It is Least expensive .
  4. It is Easy to install
  5. High-speed capacity
  6. This cable can only be used for shorter distances because of attenuation.

2. COAXIAL CABLE

  1. It has an outer plastic covering containing an insulation layer made of PVC or Teflon and 2 parallel conductors each having a separate insulated protection cover.
  2. The coaxial cable transmits information in two modes:
    1. Baseband mode(dedicated cable bandwidth)
    2. Broadband mode(cable bandwidth is split into separate ranges).
  3. Cable TVs and analog television networks widely use Coaxial cables.
  4. It has a higher frequency as compared to Twisted pair cable.
  5. The data can be transmitted at high speed.
  6. It has better shielding as compared to twisted pair cable.
  7. Easy to install and expand.
  8. It is Inexpensive
  9. Single cable failure can disrupt the entire network

3. OPTICAL FIBRE CABLE

  1. It uses the concept of refraction of light through a core made up of glass or plastic
  2. The core is surrounded by a less dense glass or plastic covering called the cladding.
  3. It is used for the transmission of large volumes of data.
  4. Increased capacity and bandwidth
  5. It is Lightweight
  6. Less signal reduction

2. UNGUIDED MEDIA

  1. It is also referred to as Wireless or Unbounded transmission media.
  2. No physical medium is required for the transmission of electromagnetic signals.
  3. An unguided transmission transmits the electromagnetic waves without using any physical medium.
  4. Therefore it is also known as wireless transmission.
  5. In unguided media, air is the media through which the electromagnetic energy can flow easily.
  6. Unguided transmission is broadly classified into three categories:
    1. Radio waves
    2. Microwaves
    3. Infrared

1. RADIO WAVES

  1. These waves are relatively simple to create and can easily pass through structures.
  2. The transmitting and receiving antennas of this do not need to be aligned.
  3. These waves have a frequency range of 3 kHz to 1GHz.
  4. In AM and FM radios, these wavelengths are employed for transmission.

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