JNTU B.Tech III DATA COMMUNICATIONS AND NETWORKS Previous Question Paper (August - 2022 - R18)

The five fundamental components of a data communication system are:

1. Message: The information (data) to be communicated, such as text, numbers, images, or audio.
2. Sender: The device that originates the data transmission (e.g., computer, workstation, telephone).
3. Receiver: The device that accepts the message.
4. Transmission Medium: The physical path by which the message travels (e.g., twisted-pair wire, fiber-optic cable, radio waves).
5. Protocol: A set of rules that govern data communication, representing an agreement between the communicating devices.

Parallel transmission involves sending multiple bits simultaneously over separate wires, making it faster but expensive for long distances. Serial transmission sends bits one after another over a single channel, which is more economical for long-distance communication. Serial transmission is further categorized into asynchronous, synchronous, and isochronous methods.

Transmission media are categorized into guided (wired) and unguided (wireless) media:

• Twisted-Pair Cable: Consists of two insulated copper wires twisted together. Merits: Cheap and easy to install. Demerits: Susceptible to electromagnetic interference and limited bandwidth.
• Coaxial Cable: Features a central conductor surrounded by insulation and a metallic shield. Merits: Higher bandwidth and better noise immunity than twisted-pair. Demerits: More expensive and physically bulkier.
• Fiber-Optic Cable: Uses light pulses through glass or plastic cores. Merits: Extremely high bandwidth, low signal attenuation, and immunity to electromagnetic interference. Demerits: High cost, fragile, and requires specialized installation skills.
• Wireless (Radio, Microwave, Infrared): Uses electromagnetic waves. Merits: Mobility, ease of deployment in difficult terrain, and broadcast capability. Demerits: Susceptible to interference, security risks, and signal degradation due to atmospheric conditions.