220-1201: CompTIA A+ Certification Exam: Core 1

When a single key stops working after debris checking, replacing just the keycap is the most cost-effective troubleshooting step. A loose or misaligned keycap can prevent key actuation. Only if this fails should the technician consider more expensive repairs like switch replacement or full keyboard replacement.

NFC (Near Field Communication) operates within a very short range of approximately 10 centimeters, while Bluetooth can connect devices up to 32 feet (10 meters) or more depending on class and version. Option D accurately describes this key difference. NFC is actually more power-efficient than Bluetooth, and both technologies can operate without initial pairing in certain modes.

Power over Ethernet (PoE) is the technology standard that allows a single Ethernet cable to carry both data and electrical power to a connected device such as an access point or IP camera. A PoE injector is the hardware device used to add that electrical current onto the data cable when the upstream switch does not natively supply PoE, making it the other component that physically delivers combined data-and-power over the cable.

Firmware is the embedded software that controls a multifunction printer's hardware and functions. When manufacturers release updates to address bugs or improve functionality like scan-to-email, they distribute firmware updates. Drivers and OS updates operate on the client computer, not the printer's internal systems.

S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) errors indicate impending or existing hard disk failure. When a drive shows S.M.A.R.T. errors, replacement is the appropriate action. Reseating cables or running disk utilities will not address hardware failure.