hardMultiple ChoiceObjective-mapped
220-1201 Practice Question: A user wants to connect their smartphone to a…
A user wants to connect their smartphone to a car's stereo system that only has an auxiliary input (3.5mm jack). The smartphone has a USB-C port and no headphone jack. Which accessory is required?
⚠ Common exam trap
The 220-1201 exam often tests the misconception that a simple cable (like a USB-C to USB-A or a 3.5mm extension) can carry analog audio, when in fact the absence of a headphone jack requires an adapter with an integrated DAC to convert digital signals to analog.
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
✓
A USB-C to 3.5mm adapter.
The car stereo only has a 3.5mm auxiliary input, so the smartphone's audio output must be converted to analog audio. A USB-C to 3.5mm adapter contains a digital-to-analog converter (DAC) that converts the smartphone's digital audio signal into an analog signal that the car stereo can accept through the 3.5mm jack.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A USB-C to USB-A cable.
Why it's wrong here
A USB-C to USB-A cable is designed to connect a USB-C port (common on modern smartphones) to a standard USB-A port (found on older computers, chargers, or some car stereos for data transfer or charging). This cable facilitates digital data exchange or power delivery, but it does not provide an analog 3.5mm audio output, which is the specific input type required by the car's auxiliary jack for sound transmission.
- ✗
A Bluetooth FM transmitter.
Why it's wrong here
A Bluetooth FM transmitter establishes a wireless audio connection by broadcasting the smartphone's audio signal over a specific FM radio frequency, which the car's radio then tunes into. While it delivers audio to the car, this method completely bypasses the physical 3.5mm auxiliary input and does not fulfill the user's requirement for a direct, wired connection to that specific port.
- ✓
A USB-C to 3.5mm adapter.
Why this is correct
A USB-C to 3.5mm adapter is the correct solution because it bridges the gap between the smartphone's digital USB-C output and the car's analog 3.5mm auxiliary input. This adapter typically integrates a Digital-to-Analog Converter (DAC) to transform the digital audio stream from the phone into an analog signal, enabling a direct and wired audio connection to the car's stereo system.
- ✗
A 3.5mm extension cable.
Why it's wrong here
A 3.5mm extension cable is designed solely to increase the reach of an existing 3.5mm audio connection between two devices that already feature compatible 3.5mm jacks. Since most contemporary smartphones have eliminated the dedicated 3.5mm headphone jack, this cable cannot directly connect the phone to the car's auxiliary input without an initial adapter to provide the necessary 3.5mm audio source from the phone.
Quick reference
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
Go deeper
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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.