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?

Answer: D. All three (CCTV, RFID, Wi-Fi LAN) are considered SHORT-RANGE devices/technologies. Short-range communication typically means under 100-300 metres for wireless or wired systems used in localised environments. (1) CLOSED-CIRCUIT TELEVISION (CCTV): video surveillance systems where cameras transmit to specific recording/monitoring stations over limited cable runs (or short wireless links). Designed for local surveillance, not long-distance broadcast. (2) RADIO FREQUENCY IDENTIFICATION (RFID): RFID tags communicate with readers over short distances. Passive RFID typically works at 1-10 cm to a few metres. Even active RFID operates at maximum 100 metres. Used in tolling, inventory, animal tagging. (3) WIRELESS LOCAL AREA NETWORK (Wi-Fi/WLAN): Wi-Fi operates within a building or campus, typical range 30-100 metres depending on the standard (802.11 family). Designed for local network access. All three are short-range, contrasted with long-range systems like cellular networks (km), satellite communication (1000s of km) or terrestrial broadcast (10s of km). Source: ITU-T / IEEE 802.11 / ISO RFID standards.