220-1101 Mobile Devices Practice Question
A user reports that their iPhone is not recognized by a Windows computer when connected via USB. The user has tried three different USB cables, all of which allow the phone to charge normally. The user also tested another iPhone with the same computer and it was recognized. The iPhone's 'Trust This Computer' prompt appeared and was accepted. Which of the following is the MOST likely cause of the issue?
⚠ Common exam trap
Candidates often assume charging success implies full port functionality, but the 220-1101 exam tests the distinction between power-only and data-capable connections in mobile device ports.
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 Lightning port on the iPhone has damaged data pins.
The fact that the iPhone charges normally but is not recognized by the computer indicates that the power pins in the Lightning connector are functioning, but the data pins are damaged or obstructed. Since another iPhone is recognized on the same computer, the issue is isolated to the original iPhone's Lightning port. The 'Trust This Computer' prompt appearing and being accepted confirms that the software trust relationship is not the problem, further pointing to a hardware data pin failure.
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 iPhone's battery needs to be replaced.
Why it's wrong here
A worn or failing battery can limit the amount of current the iPhone draws, but USB enumeration requires only a stable 5V connection and a functioning data path. If the computer enumerates the device at all, the battery is functioning; a dead battery would prevent the phone from booting, not from being identified on USB. The absence of recognition points to the Lightning port or cable, not the battery.
- ✓
The Lightning port on the iPhone has damaged data pins.
Why this is correct
The Lightning port uses separate pins for power and data; the data pins (D+ and D-) are electrically isolated from the 12V pins used for charging. If those data pins are physically damaged, corroded, or intermittently touching, the iPhone will charge normally but will be invisible to Windows because no USB handshake can occur. This is a classic symptom of pocket lint or bent pins that only break the data lines.
- ✗
The iPhone's operating system is corrupt.
Why it's wrong here
While a corrupted iOS installation causes boot failures, restore screens, or repeated logos, the bootloader (iBoot) and DFU mode still implement a basic USB interface. A Windows computer will see the phone as 'Apple Mobile Device (Recovery Mode)' or 'DFU device' even when the OS is broken. Therefore, a corrupt OS alone would not prevent the computer from recognizing the device; it would simply force a restore before normal sync.
- ✗
The iPhone's display assembly is malfunctioning.
Why it's wrong here
The display assembly has no connection to the SoC's USB controller; it communicates over the display bus and is irrelevant to data enumeration. Even with a completely unresponsive or cracked screen, the iPhone's hardware continues to function, allowing Windows to recognize it as a portable device. Failure to be recognized is a port, cable, or computer-side issue, never a display fault.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 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 220-1101 exam.