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?

(a) 1 and 2 only

(b) 2 and 3 only

(d). 1, 2 and 3

Explanation

The correct answer is (d) 1, 2, and 3. All three communication technologies mentioned in the question are considered short-range devices/technologies. Let’s discuss each option separately:

Closed-circuit Television (CCTV): CCTV is a TV system in which signals are not publicly distributed but are monitored, primarily for surveillance and security purposes. It is considered a short-range device because it operates at low transmitted power and has a limited range.
Radio Frequency Identification (RFID): RFID uses electromagnetic fields to automatically identify and track tags attached to objects. It operates at low transmitted power and has a limited range, making it a short-range device.
Wireless Local Area Network (WLAN): WLAN is a group of colocated computers or other devices that form a network based on radio transmissions rather than wired connections. It operates at high-frequency radio waves and has a limited range, making it a short-range device.

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Short Range Devices (SRD): SRD are radio devices that offer a low risk of interference with other radio services, usually because their transmitted power, and hence their range, is low.
Applications of SRD: SRD can be applied to many different types of wireless equipment, including access control, alarms and movement detectors, closed-circuit television (CCTV), cordless audio devices, industrial control, local area networks, medical implants, metering devices, remote control, radio frequency identification (RFID), and road transport telematics.
Regulatory aspects: Short-range devices often benefit from a relaxed regulatory regime compared with other radio communications equipment. As a general principle, a user is license-free to operate such equipment, although some specific cases may require an individual license.
Frequency bands: Short-range devices operate in various frequency bands, such as 13.56 MHz (mainly used for RFID), 40 MHz, 433 MHz, 2.4 GHz, and 5.8 GHz.