UPSC Prelims 2022 Q36: Science & Technology – Computer & Information Technology
Consider the following communication technologies:
1. Closed - circuit Television
2. Radio Frequency Identification
3. Wireless Local Area Network
Which of the above are considered Short - Range devices/technologies?
- (a) 1 and 2 only
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3
Answer: (d) 1, 2 and 3
Explanation
Short-Range Devices (SRDs)
Short-range devices are radio devices that work over short distances with low power, usually in licence-exempt bands.
| Technology | Range | SRD? |
|---|---|---|
| 1. Closed-circuit television (CCTV) | Local camera links (wireless CCTV) within a building or site | Yes |
| 2. RFID | A few centimetres to a few metres | Yes |
| 3. Wireless LAN (Wi-Fi) | About 50–100 m | Yes |
Other common SRDs:
| Device | Use |
|---|---|
| Bluetooth | Headphones, phones |
| NFC | Contactless payments |
| Zigbee | Smart-home sensors |
| Car key fobs | Remote locking |
In India, many SRD bands are delicensed by the Department of Telecommunications for low-power use.
Answer: (d) 1, 2 and 3.
Why each option is right or wrong
- (a) Incorrect. It leaves out Wi-Fi (WLAN), a standard short-range technology.
- (b) Incorrect. It leaves out CCTV, whose wireless links are short-range.
- (c) Incorrect. It leaves out RFID, which works only over very short distances.
- (d) CORRECT. CCTV, RFID and WLAN are all treated as short-range technologies.
Key point
Short-range devices: CCTV links, RFID, Wi-Fi, Bluetooth, NFC, Zigbee — low power, short distance, often delicensed bands.
Remember
CCTV, RFID and Wi-Fi are all short-range technologies.
Common mistakes
- Thinking CCTV is wired-only; wireless CCTV links are short-range devices.
- Assuming Wi-Fi is long-range; its range is about 100 m.
- Confusing RFID with GPS tracking, which uses satellites.
Exam tip
Short-range = within a room, building or campus. All three fit.
Sources
- Department of Telecommunications — Delicensed frequency bands for SRDs
- ETSI — Short Range Devices standards (EN 300 220)