IPA IP 2020 Question 98
A question IPA Japan published in 令和2年度 10月 ITパスポート試験 公開問題 問98, translated into English. ITPEC is based on the same exams.
In building an IoT area network, the use of communication standards ① through ③ is being considered. When these communication standards are classified into wired and wireless, which of the following lists all and only those that are classified as wireless networks?
Explanation
① BLE and ③ ZigBee — both are short-range, low-power radio standards; PLC sends its signals over power cables.
- •① BLE (Bluetooth Low Energy) — the power-saving part of Bluetooth, added in version 4.0: wireless
- •② PLC (Power Line Communication) — superimposes high-frequency signals on the power lines that supply electricity, so the cables double as the network: wired
- •③ ZigBee — a low-power, low-rate radio standard built on IEEE 802.15.4, used for sensor networks that form a mesh: wireless
Answer (c)
Why not others:
- •(a) — leaves out ZigBee and includes PLC, which runs over cables
- •(b) — includes PLC: it needs no new wiring, but it is still communication over wires
- •(d) — includes PLC and leaves out BLE, which is radio
Key rule: In IoT area networks, BLE, ZigBee and Wi-Fi are wireless; PLC is wired, using the existing power lines as the cable.
Networks · AI-written, may contain errors
This question comes from the past questions IPA Japan publishes, translated into English by ITPEC Practice. ITPEC Practice is an independent study tool and is not affiliated with IPA or ITPEC. See the original paper (PDF) or Report an issue.