220-1101 Question 17
Single answerNear-field communication (NFC)A technician is configuring company-issued smartphones so employees can tap their phones on office badge readers to authenticate and unlock secure print jobs. Several users report that the feature works only when they place the phone very close to the reader, and one employee asks whether the phone can stay in a pocket and still communicate. Which statement best explains how this technology should function?
- A
The phones are using NFC, which is designed for very short-range communication and typically requires the device to be within a few centimeters of the reader.
- B
The phones are using Bluetooth, which should allow authentication from several meters away without pairing when the reader is in discovery mode.
- C
The phones are using infrared, which can pass through clothing as long as the phone is pointed toward the badge reader.
- D
The phones are using Wi-Fi Direct, which is intended for tap-to-authenticate access control at close range without network configuration.
Show answer and explanation
Correct answer: A
Explanation
This scenario describes near-field communication (NFC), which CompTIA A+ Core 1 expects candidates to recognize as a short-range wireless technology used for contactless payments, device pairing, and access control. NFC operates at very close distances, typically up to about 4 cm, so users generally need to place the phone close to the reader for reliable communication. That short range is a normal characteristic, not a malfunction. In real deployments, performance can also be affected by phone placement, protective cases, and antenna alignment. Vendor and standards documentation for NFC-based access systems and the NFC Forum consistently describe NFC as a close-proximity technology rather than a room-range wireless method.
- A. Correct.
Correct. Near-field communication (NFC) is a short-range wireless technology commonly used for contactless payments, badge emulation, and tap-based authentication. In practice, the phone usually must be brought within a few centimeters of the reader. This is why the feature works only when the device is very close, and it also explains why leaving the phone in a pocket may prevent reliable communication depending on distance, orientation, case thickness, and reader sensitivity.
- B. Incorrect.
Incorrect. Bluetooth operates over a much longer range than NFC and is not the standard technology for simple tap-to-authenticate badge-reader interactions. Bluetooth typically involves discovery, pairing, or app-based workflows depending on the implementation, rather than the immediate close-proximity tap behavior described in the scenario. A candidate might choose this option because Bluetooth is common on smartphones, but the scenario specifically matches NFC behavior.
- C. Incorrect.
Incorrect. Infrared requires line-of-sight and does not pass through clothing or other opaque barriers in the way described. It is also not the standard method used for modern phone-to-reader tap authentication systems. Someone might choose this because infrared is also short range, but its requirement for direct alignment makes it a poor fit for badge-reader tap access use cases.
- D. Incorrect.
Incorrect. Wi-Fi Direct is used for peer-to-peer wireless networking between devices and is not the normal technology for tap-based credential exchange with a badge reader. It also does not depend on the very short read distance associated with contactless access systems. This distractor is plausible because it is a wireless technology supported on many mobile devices, but it does not match the real-world access-control scenario.