easyMultiple ChoiceObjective-mapped
220-1201 Practice Question: That their VoIP phone works but the PC connected…
A user reports that their VoIP phone works but the PC connected to the phone's passthrough port has no network access. What should the technician check first?
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
✓
The Ethernet cable between the phone and the PC.
This question tests understanding of VoIP passthrough ports. The PC's lack of connectivity is often due to a faulty or unseated Ethernet cable between the phone and PC. The phone itself is working, so the upstream connection is fine.
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 PC's IP configuration.
Why it's wrong here
The PC's IP configuration is a Layer 3 concern. If the PC cannot establish a physical or data link connection through the VoIP phone's passthrough port, it will not even be able to obtain an IP address via DHCP or utilize a static IP. The problem statement implies a more fundamental connectivity issue preventing the PC from reaching the network, making IP configuration a secondary symptom rather than the root cause of the missing link.
- ✓
The Ethernet cable between the phone and the PC.
Why this is correct
VoIP phones often include a passthrough Ethernet port, allowing a single wall jack to serve both the phone and a connected PC. If the phone itself is operational, its connection to the network switch is functional. However, the PC relies on a separate Ethernet cable connecting its network interface card to the phone's passthrough port to receive network access. A faulty or disconnected cable in this specific segment would directly explain why the PC has no network connectivity while the phone continues to work.
- ✗
The VoIP phone's firmware version.
Why it's wrong here
The VoIP phone's firmware governs its internal operations, such as call processing, display functionality, and its ability to register with a call server. If the phone is working, it indicates that its core firmware is stable and performing its primary functions correctly. Firmware issues would typically manifest as the phone itself failing to operate, experiencing call quality problems, or exhibiting erratic behavior, rather than selectively disabling only the passthrough port while the phone remains fully functional.
- ✗
The switch port the phone is connected to.
Why it's wrong here
The statement that the VoIP phone "works" directly confirms that the switch port it is connected to is providing proper power (if Power over Ethernet, PoE) and data connectivity. If the switch port were faulty, the phone would either not power on, fail to register with the VoIP system, or be unable to make calls. Since the phone is operational, the integrity of the upstream switch port is validated, shifting the focus to components downstream from the phone.
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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.