FC0-U71 Infrastructure Practice Question
Which device converts the signal from an ISP into a digital signal that a computer can use?
⚠ Common exam trap
FC0-U71 often tests the confusion between modem and router, tricking candidates into choosing router because it's the device they associate with 'internet,' when the question specifically asks about signal conversion.
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
✓
Modem
A modem (modulator-demodulator) converts the ISP's signal — whether analog (DSL, cable, POTS) or optical (fiber ONT) — into a digital signal that a computer or router can use. It is the demarcation device between the ISP's WAN medium and the customer's LAN. This matches the question's definition exactly.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Switch
Why it's wrong here
A switch forwards Ethernet frames between devices on the same LAN and performs no signal conversion from the ISP's medium. It is tempting because it is the central connectivity device in a wired network, and would be correct when the question asks which device connects multiple wired hosts within one subnet.
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Access point
Why it's wrong here
An access point bridges wireless clients onto a wired LAN; it does not demodulate the ISP's incoming signal. It is tempting because it is the customer-premises device most users see, and would be correct when the question asks which device provides Wi-Fi connectivity to wireless clients.
- ✓
Modem
Why this is correct
A modem modulates and demodulates the carrier signal from the ISP's line, converting it into digital data a computer can process. Routers, switches and access points forward or distribute traffic but do not perform this analogue-to-digital conversion.
- ✗
Router
Why it's wrong here
A router forwards packets between networks and performs NAT, but does not demodulate the ISP's incoming signal into digital data. It is tempting because routers sit at the network edge, and would be correct when the question asks which device directs traffic between your LAN and the internet.
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Same concept, more angles
2 more ways this is tested on FC0-U71
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which network device converts the signal from an Internet Service Provider (ISP) into a digital signal that a home network can use?
easy- A.Access point
- B.Switch
- C.Router
- ✓ D.Modem
Why D: A modem modulates and demodulates signals from the ISP (e.g., cable, DSL) into digital data for the home network.
Variation 2. Which device converts the signal from an ISP (e.g., cable or fiber) into a digital signal that a home network can use?
medium- A.Access point
- B.Router
- C.Switch
- ✓ D.Modem
Why D: A modem (modulator-demodulator) converts the analog or optical signal from an ISP's cable, DSL, or fiber connection into a digital signal that the home network can use. It is the demarcation device between the ISP's medium and the customer's equipment.
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This FC0-U71 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 FC0-U71 exam.