mediumMultiple ChoiceObjective-mapped
220-1201 Practice Question: A technician is troubleshooting a home network…
A technician is troubleshooting a home network where the 5 GHz band works fine, but the 2.4 GHz band is extremely slow and drops connections. The router is placed near a cordless phone base station. Which type of interference is most likely occurring?
⚠ Common exam trap
This question tests the candidate's ability to distinguish between common 2.4 GHz interference sources. The trap is to assume that any 2.4 GHz device (like Bluetooth or a microwave) causes similar interference, but the specific symptoms of persistent, severe degradation due to a nearby cordless phone base station point to intentional RF interference from a device that operates continuously on the same frequency band.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
RF interference from the cordless phone base
The 2.4 GHz band is shared by many consumer devices, including cordless phones that operate in the 2.4 GHz ISM band. The proximity of the router to the cordless phone base station causes RF interference, which degrades the 2.4 GHz signal, leading to slow speeds and dropped connections, while the 5 GHz band remains unaffected because it operates on a different frequency range.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Bluetooth interference
Why it's wrong here
Bluetooth devices operate in the 2.4 GHz band, similar to Wi-Fi. However, Bluetooth typically uses frequency hopping spread spectrum (FHSS) and lower power outputs, making its interference more transient and localized. While it can cause minor, intermittent disruptions, it is less likely to be the source of sustained, significant performance degradation across an entire 2.4 GHz Wi-Fi network compared to other continuous emitters.
- ✗
Microwave oven interference
Why it's wrong here
Microwave ovens also operate within the 2.4 GHz Industrial, Scientific, and Medical (ISM) band, which can cause significant electromagnetic interference with Wi-Fi signals. However, this interference is typically intermittent, occurring only when the microwave oven is actively in use for heating food. Since the problem described is persistent, a microwave oven is an unlikely cause for continuous poor network performance.
- ✗
Co-channel interference from a neighboring Wi-Fi network
Why it's wrong here
Co-channel interference from a neighboring Wi-Fi network occurs when multiple access points use the same or overlapping channels, leading to contention and reduced throughput. While this is a common issue in crowded 2.4 GHz environments, the problem statement indicates that the 5 GHz band is performing normally. This distinction suggests the interference is specific to the 2.4 GHz band and not a general network congestion issue affecting both frequency ranges.
- ✓
RF interference from the cordless phone base
Why this is correct
Many older cordless phone systems operate continuously in the 2.4 GHz ISM band, directly overlapping with Wi-Fi channels 1-11. These base stations emit a relatively strong and constant radio frequency (RF) signal, which can severely degrade the signal-to-noise ratio for Wi-Fi devices operating on the same band. This persistent, localized interference perfectly explains poor performance on the 2.4 GHz band while the 5 GHz band remains unaffected.
Go deeper
Related to this question
About these practice questions
Courseiva writes every 220-1201 question from scratch — 972 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1201 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1201 exam.