Q. Consider the following communication technologies: - Closed-circuit Television
- Radio Frequency Identification
- Wireless Local Area Network
Which of the above are considered Short-Range devices/technologies? (UPSC Prelims 2022)
Answer:
1, 2 and 3
Notes: The correct answer is
[D] 1, 2 and 3. Short-Range Devices (SRDs) are radio transmitters that provide unidirectional or bidirectional communication and which have low capability of causing interference to other radio equipment.
- Closed-circuit Television (1 – Correct): CCTV systems, especially modern wireless versions, operate as short-range devices. Even traditional wired systems are designed for localized surveillance within a limited area (building or campus), fitting the "short-range" context of localized communication infrastructure.
- Radio Frequency Identification (2 – Correct): RFID is a classic example of short-range technology. It uses electromagnetic fields to identify and track tags attached to objects. The range typically varies from a few centimeters (NFC) to a few meters (UHF RFID), making it strictly a short-range communication tool.
- Wireless Local Area Network (3 – Correct): WLAN (commonly known as Wi-Fi) is designed to provide high-speed data communication within a small geographic area, such as a home, office, or school. Its typical range is approximately 20 to 100 meters, classifying it as a short-range wireless technology.
Short-range devices generally operate on license-exempt bands (like the ISM band) and are characterized by low power consumption and limited coverage areas compared to long-range technologies like cellular networks (4G/5G) or satellite communication.