4.6 Data Communication

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 v  Data Communication: -

Ø  Data Communication refers to the exchange of data between two or more devices through a transmission medium such as wired cables or wireless signals.

Ø  It is the foundation of computer networks and the Internet.

Ø  Key Elements of Data Communication

·        Sender (Transmitter): The device that sends the data (e.g., computer, smartphone).

·        Receiver: The device that receives the data (e.g., server, printer).

·        Message (Data): The information to be communicated (text, audio, video, etc.).

·        Transmission Medium: The physical path or channel for data transfer (cables, radio waves).

·        Protocol: A set of rules that governs data transmission (e.g., TCP/IP, HTTP). Types of Data Communication.

 

Ø  Types of Data Communication:

1.     Wired Communication:

·        Uses cables like Twisted Pair, Coaxial Cable, Fiber Optic.

·        High speed and security but limited mobility.

 

2.     Wireless Communication:

·        Uses Radio Waves, Microwaves, Infrared, Satellite.

·        Provides mobility but may face interference.

 

Ø  Modes of Data Communication

1.     Simplex: Data flows in one direction only (e.g., keyboard → computer).

2.     Half Duplex: Data flows in both directions, but one at a time (e.g., walkietalkies).

3.     Full Duplex: Data flows in both directions simultaneously (e.g., telephone).

 

1)    Wired (Ethernet, Fiber): -

Ø  Wired data communication involves the transmission of data using physical cables.

Ø  It is widely used in computer networks due to its reliability, high speed, and security.

Ø  The two most common wired communication technologies are Ethernet and Fiber Optics

a.      Ethernet: - Ethernet is a widely used technology for local area networks (LANs) that uses copper cables (such as twisted pair cables) to transmit data in the form of electrical signals.

 

Key Features:

·      Uses LAN architecture (star or bus topology).

·      Data is transmitted via electrical pulses.

·      Common cable types: Cat5, Cat5e, Cat6, Cat6a.

·      Standard speeds: 10 Mbps, 100 Mbps (Fast Ethernet), 1 Gbps (Gigabit Ethernet), 10 Gbps.

 

Advantages:

·        Cost effective and easy to install.

·        Reliable for short to medium distances (up to 100 meters per segment).

·        Supports highspeed data transfer.

 

Disadvantages:

·        Limited distance compared to fiber (signal loss over long runs).

·        Susceptible to electromagnetic interference (EMI).

 

b.     Fiber Optic Communication Fiber optic communication uses thin strands of glass or plastic fibers to transmit data as light pulses, offering extremely highspeed communication over long distances.

 

Key Features:

·        Immune to electromagnetic interference.

·        Supports long distance communication (up to several kilometers).

·        Common types: Single mode fiber (SMF) for long distances, Multimode fiber (MMF) for shorter distances.

·        Speeds: 1 Gbps to 400 Gbps and beyond.

 

Advantages:

·        Extremely high bandwidth and speed.

·        Very low signal loss over long distances.

·        Secure transmission as tapping is difficult.

 

Disadvantages:

·        Expensive to install and maintain.

·        Requires specialized equipment and skills.



2)  Wireless (Wi-Fi, Bluetooth): –

Ø  Wireless data communication transmits data without physical cables, using radio waves, microwaves, or infrared signals.

Ø  It provides flexibility and mobility, commonly used in LANs, PANs, and mobile communication.

 

a)     WiFi (Wireless Fidelity): - WiFi is a wireless networking technology that allows devices to connect to a local area network (LAN) and the internet via radio waves.

 

Key Features:

·        Operates under IEEE 802.11 standards.

·        Frequency bands: 2.4 GHz (longer range, slower) and 5 GHz (shorter range, faster).

·        Provides highspeed connectivity for laptops, smatphones, IoT devices.

 

Advantages:

·        No physical wires, offering mobility.

·        Can connect multiple devices simultaneously.

·        Relatively high speed (up to several Gbps with modern standards like WiFi 6/6E).

 

Disadvantages:

·        Limited range (\~30100 meters indoors).

·        Susceptible to signal interference from walls, appliances, and other networks.

·        Less secure than wired unless encryption (WPA3) is used.

 

b)    Bluetooth: - Bluetooth is a shortrange wireless communication technology mainly used for device-to-device communication in a Personal Area Network (PAN).

 

Key Features:

·        Operates in the2.4 GHz ISM band.

·        Typical range:10 to 100 meters, depending on class.

·        Supports low-power communication for headphones, keyboards, smart watches, IoT devices.

 

Advantages:

·        Low power consumption.

·        Easy pairing for shortrange communication.

·        No internet required for device-to-device communication.

 

Disadvantages:

·        Slower data transfer (usually up to 3 Mbps for classic Bluetooth, higher for BLE 5.x).

·        Short range compared to WiFi.

·        Can be affected by interference from other wireless devices.




v  Bandwidth & Speed Concepts (bps, Mbps, Gbps): -

Ø In data communication, bandwidth and speed are crucial for understanding how fast data is transmitted between devices.

Ø These are usually measured in bits per second (bps) and its multiples.

1.     Bandwidth: -

·        Bandwidth is the maximum rate at which data can be transmitted over a network connection in a given time.

·        Measured in Bits per second (bps) and higher units like Kbps, Mbps, Gbps, Tbps.

·        Higher bandwidth = more data transfer per second.

 

2.     Speed: -

·        Speed refers to how fast data actually travels through the network, often affected by bandwidth, network congestion, and latency.

·        Difference between Bandwidth and Speed:

Bandwidth: Maximum capacity of the channel.

Speed: Actual data transfer rate at a moment


Common Units of Measurement

























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