easyMultiple ChoiceObjective-mapped
220-1201 Practice Question: A customer reports that their internet connection…
A customer reports that their internet connection drops frequently during rainstorms. They have a DSL line and a standard modem. Which factor most likely causes this issue?
⚠ Common exam trap
CompTIA A+ often tests the distinction between environmental factors affecting physical-layer media (like copper DSL) versus logical or device-level issues, tempting candidates to blame the modem or ISP when the root cause is line degradation from moisture.
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
✓
Moisture in the copper line causes signal degradation.
DSL operates over copper telephone lines, which are susceptible to moisture ingress during rainstorms. Water in the line increases signal attenuation and introduces impedance mismatches, causing the modem to lose synchronization with the DSLAM. This results in frequent disconnections, as the DSL signal degrades below the threshold required for a stable link.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The modem's power supply is failing.
Why it's wrong here
A failing power supply typically manifests as intermittent power loss, unexpected reboots, or complete device failure, irrespective of external environmental conditions. Such an internal hardware malfunction would cause connection drops randomly or consistently, rather than specifically correlating with precipitation events like rainstorms, which points to an external line issue.
- ✓
Moisture in the copper line causes signal degradation.
Why this is correct
Moisture ingress into compromised insulation or poorly sealed connection points along a DSL copper line significantly alters its electrical characteristics, increasing capacitance and resistance. This impedance mismatch and signal attenuation degrade the signal-to-noise ratio (SNR), making it difficult for the DSL modem to maintain synchronization with the Digital Subscriber Line Access Multiplexer (DSLAM) at the central office, resulting in frequent connection drops specifically during rainy conditions.
- ✗
The customer's router is overheating.
Why it's wrong here
Router overheating typically stems from internal factors such as inadequate ventilation, accumulated dust obstructing airflow, or sustained heavy processing loads, leading to thermal throttling or unexpected reboots. Rainstorms, generally associated with cooler ambient temperatures, do not directly cause electronic components to overheat; therefore, this internal hardware issue would not specifically correlate with precipitation events but rather with continuous operational stress or environmental factors unrelated to rain.
- ✗
The ISP is throttling the connection during storms.
Why it's wrong here
Internet Service Providers (ISPs) implement throttling as a deliberate network management strategy, typically based on subscriber data usage limits, network congestion management policies, or specific service tier agreements. Throttling is a policy-based action designed to regulate bandwidth, not a physical phenomenon triggered by environmental conditions like rainstorms, which would instead cause physical layer signal integrity problems rather than a controlled reduction in speed.
Go deeper
Related to this question
Learn chapter
Internet Connection Types
Key term
DSL
DSL (Digital Subscriber Line) is a technology that uses existing telephone lines to provide high-speed internet access without interrupting your phone service.
Key term
Synchronization
Synchronization is the process of making sure two or more systems, devices, or pieces of data stay exactly matched and up-to-date with each other.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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