220-1101 Question 133
Single answerInjectorsA technician is installing a ceiling-mounted wireless access point in an older office area that does not have an electrical outlet near the mounting location. The network switch in the wiring closet does not provide PoE. The technician needs to power the access point while still using the existing Ethernet cabling for network connectivity, with minimal changes to the building. Which device should the technician use?
- A
PoE injector
- B
Cable modem
- C
Loopback plug
- D
Toner probe
Show answer and explanation
Correct answer: A
Explanation
The best answer is PoE injector. In real deployments, a PoE injector is commonly used when a network device must be installed in a location without a nearby power outlet and the existing switch does not support Power over Ethernet. The injector is placed between the switch and the endpoint device: one Ethernet connection carries data from the switch into the injector, and another Ethernet connection carries both data and power from the injector to the access point. This approach aligns with common Ethernet and PoE deployment practices used for wireless access points, IP phones, and cameras. A+ Core 1 expects candidates to recognize the purpose of injectors in practical network installations.
- A. Correct.
Correct. A PoE injector adds electrical power to an Ethernet cable so a device such as a wireless access point, IP camera, or VoIP phone can receive both data and power over the same cable. This is the practical solution when the switch itself does not support PoE and running new electrical wiring is undesirable.
- B. Incorrect.
Incorrect. A cable modem connects a local network to an ISP over a cable provider's coaxial infrastructure. It does not inject power onto Ethernet cabling and would not solve the problem of powering an access point.
- C. Incorrect.
Incorrect. A loopback plug is used for testing ports and verifying transmission functionality on network or interface connections. It is a diagnostic tool, not a device for delivering power to network equipment.
- D. Incorrect.
Incorrect. A toner probe is used to trace and identify cables in walls, patch panels, or bundles. It helps locate cabling but does not provide electrical power or network switching functionality.