The answer is that the car USB port does not supply enough current. This is the most likely issue because car USB ports, especially older or standard models, often deliver only 0.5 amps, while modern Android phones require higher amperage—typically 1.0 to 2.4 amps—to initiate or sustain charging. Even if the port powers other devices like a GPS or a USB fan, those gadgets may draw less current, so the phone’s charging circuit simply refuses to accept the insufficient power, resulting in no charge at all. On the CompTIA A+ Core 1 220-1201 exam, this scenario tests your understanding of power specifications and current draw under the mobile device troubleshooting domain; a common trap is assuming the port is broken because it works with other devices. Remember the memory tip: “Amps are the flow, not the voltage—if the phone won’t go, the current’s too low.”
220-1201 Mobile Device Connection Methods Practice Question
This 220-1201 practice question tests your understanding of mobile device connection methods. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A user's Android phone will not charge when plugged into a car's USB port, but charges fine with a wall adapter. The car's USB port powers other devices. What is the most likely issue?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The car USB port does not supply enough current.
Car USB ports often provide limited current (0.5A), which may be insufficient for fast charging or even maintaining charge on modern phones. The phone's charging circuit may require more current than the port supplies, so it does not charge.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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 car's USB port is faulty.
Why it's wrong here
The port powers other devices, so it is functional; the issue is current output, not a fault.
✗
The phone's USB port is damaged.
Why it's wrong here
The phone charges with a wall adapter, so its port is working correctly.
✓
The car USB port does not supply enough current.
Why this is correct
Car USB ports typically output 0.5A, while modern phones may need 1A or more to charge; insufficient current prevents charging.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
✗
The USB cable is incompatible.
Why it's wrong here
The same cable works with a wall adapter, so the cable is not the problem.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Trap categories for this question
Command / output trap
The port powers other devices, so it is functional; the issue is current output, not a fault.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 220-1201 question in full detail.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 220-1201 NAT questions on configuration and troubleshooting.
Mobile Device Connection Methods — This question tests Mobile Device Connection Methods — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The car USB port does not supply enough current. — Car USB ports often provide limited current (0.5A), which may be insufficient for fast charging or even maintaining charge on modern phones. The phone's charging circuit may require more current than the port supplies, so it does not charge.
What should I do if I get this 220-1201 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 220-1201 NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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