Data Communication — Exam Power Notes
Quick Revision Guide
1. What Is Data Communication?
Data communication is the exchange of information between devices through a communication medium. A basic system
includes a sender, receiver, message, medium, and protocol.
2. Transmission Modes
Mode Meaning
Simplex Communication in one direction only.
Half-Duplex Two-way communication, but not simultaneously.
Full-Duplex Two-way communication at the same time.
3. Analog vs Digital
Analog signals vary continuously. Digital signals use discrete values, commonly represented with binary data.
4. Transmission Media
Guided media include twisted-pair, coaxial, and fiber-optic cables. Unguided media include radio, microwave, and infrared
transmission.
5. Bandwidth and Data Rate
Bandwidth describes the frequency range a channel can carry. Data rate describes the amount of data transmitted per unit
of time.
6. Network Topologies
Common topologies are bus, star, ring, mesh, and hybrid. Star topology connects devices through a central device.
7. Multiplexing
Multiplexing allows multiple signals to share a communication channel. Examples include frequency-division, time-division,
and wavelength-division multiplexing.
8. Switching
Circuit switching uses a dedicated path. Packet switching divides data into packets that travel through shared network
paths.
9. Error Detection
Parity, checksums, and cyclic redundancy checks (CRC) are common techniques for detecting transmission errors.
10. Protocols
A protocol is a set of rules governing communication, including data format, addressing, timing, and error handling.
11. Short Q&A;
Q: What is a protocol? A: Rules for communication. Q: What is full-duplex? A: Simultaneous two-way communication. Q:
What is packet switching? A: Sending data as packets through shared network paths.
12. MCQs
1) Simultaneous two-way communication? A) Simplex B) Half-duplex C) Full-duplex D) None — Answer: C. 2) Which uses
light signals? A) Fiber optic B) Coaxial C) Twisted pair D) Radio — Answer: A. 3) Which detects transmission errors? A)
CRC B) HTML C) CPU D) BIOS — Answer: A. 4) Which topology uses a central device? A) Star B) Ring C) Bus D) Mesh —
Quick Revision Guide
1. What Is Data Communication?
Data communication is the exchange of information between devices through a communication medium. A basic system
includes a sender, receiver, message, medium, and protocol.
2. Transmission Modes
Mode Meaning
Simplex Communication in one direction only.
Half-Duplex Two-way communication, but not simultaneously.
Full-Duplex Two-way communication at the same time.
3. Analog vs Digital
Analog signals vary continuously. Digital signals use discrete values, commonly represented with binary data.
4. Transmission Media
Guided media include twisted-pair, coaxial, and fiber-optic cables. Unguided media include radio, microwave, and infrared
transmission.
5. Bandwidth and Data Rate
Bandwidth describes the frequency range a channel can carry. Data rate describes the amount of data transmitted per unit
of time.
6. Network Topologies
Common topologies are bus, star, ring, mesh, and hybrid. Star topology connects devices through a central device.
7. Multiplexing
Multiplexing allows multiple signals to share a communication channel. Examples include frequency-division, time-division,
and wavelength-division multiplexing.
8. Switching
Circuit switching uses a dedicated path. Packet switching divides data into packets that travel through shared network
paths.
9. Error Detection
Parity, checksums, and cyclic redundancy checks (CRC) are common techniques for detecting transmission errors.
10. Protocols
A protocol is a set of rules governing communication, including data format, addressing, timing, and error handling.
11. Short Q&A;
Q: What is a protocol? A: Rules for communication. Q: What is full-duplex? A: Simultaneous two-way communication. Q:
What is packet switching? A: Sending data as packets through shared network paths.
12. MCQs
1) Simultaneous two-way communication? A) Simplex B) Half-duplex C) Full-duplex D) None — Answer: C. 2) Which uses
light signals? A) Fiber optic B) Coaxial C) Twisted pair D) Radio — Answer: A. 3) Which detects transmission errors? A)
CRC B) HTML C) CPU D) BIOS — Answer: A. 4) Which topology uses a central device? A) Star B) Ring C) Bus D) Mesh —
