1. Overview
- Transmission media = Path through which data travels between devices.
- Two main types:
- Wired (Guided Media): Data travels through physical cables.
- Wireless (Unguided Media): Data travels through air (no cables).
2. Wired (Guided) Media
| Type | Description | Use Cases | Key Features |
|---|---|---|---|
| Twisted Pair | Two copper wires twisted to reduce interference. | LAN (Ethernet), Telephones. | Cheap, flexible, limited bandwidth (~100m). |
| Coaxial Cable | Single copper core with insulation layers. | Cable TV, Internet. | Better noise resistance, faster than twisted pair. |
| Fiber Optic | Uses light through glass/plastic fibers. | High-speed internet, telecom. | Very high speed, long distance, expensive, immune to interference. |
3. Wireless (Unguided) Media
| Type | Description | Use Cases | Key Features |
|---|---|---|---|
| Radio Waves | Low-frequency EM waves for wide coverage. | FM/AM radio, Wi-Fi. | Long distance, but more interference. |
| Microwaves | High-frequency waves for direct line-of-sight. | Satellites, mobile networks. | High speed, needs clear line of sight. |
| Infrared (IR) | Light waves below visible spectrum. | TV remotes, short-range IoT devices. | Short range, cannot pass walls. |
| Satellite | Signals sent to/from orbiting satellites. | GPS, global communication. | Global coverage, high latency (delay). |
4. Wired vs Wireless (Quick Comparison)
| Feature | Wired | Wireless |
|---|---|---|
| Installation | Needs cables, complex. | Easy, no cables. |
| Cost | Higher (especially fiber). | Lower. |
| Speed | Faster (esp. fiber optic). | Slower, depends on tech. |
| Mobility | Limited. | High mobility. |
| Interference | Less (esp. fiber). | More prone to interference. |
5. Key Points
- Twisted Pair: Common in Ethernet (Cat-5, Cat-6).
- Coaxial: For cable TV and older LANs.
- Fiber Optic: Best for high speed and long distances.
- Microwave: Needs line-of-sight (e.g., towers, satellites).
- Infrared: Short range, for devices in the same room.
6. Quick Recap Table
| Media Type | Range | Speed | Cost |
|---|---|---|---|
| Twisted Pair | Short (<100m) | Medium (10 Mbps–10 Gbps) | Low |
| Coaxial Cable | Medium (<500m) | Medium (10 Mbps–1 Gbps) | Moderate |
| Fiber Optic | Long (>10 km) | Very High (1–100 Gbps) | High |
| Radio Waves | Long (>1 km) | Medium | Low |
| Microwaves | Medium (~80 km) | High | Moderate |
| Infrared | Short (<10m) | Low | Low |
MCQ
1. Which transmission medium provides the highest speed?
- A) Coaxial Cable
- B) Twisted Pair Cable
- C) Optical Fiber
- D) Electrical Cable
- Answer: C) Optical Fiber
2. What type of cable is used for voice and data communications?
- A) Coaxial Cable
- B) Fiber-optic Cable
- C) Twisted Pair Cable
- D) All of the above
- Answer: C) Twisted Pair Cable
3. What is an example of unguided transmission media?
- A) Fiber-optic Cable
- B) Coaxial Cable
- C) Radio Waves
- D) Twisted Pair Cable
- Answer: C) Radio Waves
4. In fiber-optic cables, the signal is transmitted using:
- A) Electrical signals
- B) Infrared light
- C) Light waves
- D) Radio waves
- Answer: C) Light waves
5. Radio waves are:
- A) Omnidirectional
- B) Unidirectional
- C) Bidirectional
- D) Single-direction
- Answer: A) Omnidirectional
6. Which cable consists of a central conductor and an outer shield?
- A) Twisted Pair Cable
- B) Coaxial Cable
- C) Fiber-optic Cable
- D) Ethernet Cable
- Answer: B) Coaxial Cable
7. Which transmission medium uses light signals?
- A) Fiber-optic Cable
- B) Coaxial Cable
- C) Ethernet Cable
- D) Twisted Pair Cable
- Answer: A) Fiber-optic Cable
8. What is a disadvantage of wireless communication compared to wired communication?
- A) Limited bandwidth
- B) High installation cost
- C) Limited mobility
- D) None of the above
- Answer: A) Limited bandwidth
9. Which medium is best for long-distance data transmission with minimal signal loss?
- A) Twisted Pair Cable
- B) Fiber-optic Cable
- C) Coaxial Cable
- D) Radio Waves
- Answer: B) Fiber-optic Cable
10. In an optical fiber, what causes signal propagation?
- A) Refraction
- B) Reflection
- C) Diffraction
- D) Modulation
- Answer: B) Reflection
For more detailed study, refer to resources like ExamRadar, MCQs Mentor, and CSEStudy247.