220-1102 Question 227
Single answerDockA user with a company-issued laptop reports that after connecting to a USB-C docking station at their desk, the wired keyboard, mouse, and external monitor all work, but the laptop does not charge. The same dock charges another employee's laptop without issue. You verify that the dock's power adapter is connected and the dock firmware is current. What is the MOST likely cause?
- A
The laptop's USB-C port supports data and video output but does not support USB Power Delivery input
- B
The external monitor is drawing too much power from the dock, preventing laptop charging
- C
The dock must be connected through a USB-A to USB-C adapter before power can pass to the laptop
- D
The laptop requires Bluetooth pairing with the dock before charging can begin
Show answer and explanation
Correct answer: A
Explanation
The best answer is that the laptop's USB-C port lacks support for USB Power Delivery input, even though it supports enough USB-C functionality for peripherals and external display output. In practice, USB-C is a connector type, not a guarantee of full feature support. A technician should verify the laptop model's specifications for USB-C capabilities, including charging/PD input and DisplayPort Alt Mode support. This aligns with common manufacturer documentation from vendors such as Dell, HP, and Lenovo, which often note that some USB-C ports support data/video only while others also support charging. As a best practice, confirm port symbols, review the system manual, and test with the OEM charger or a known-compatible dock.
- A. Correct.
Correct. A common real-world issue with USB-C docks is that not all USB-C ports support the same features. Some laptop USB-C ports support data and DisplayPort Alt Mode for video, but not USB Power Delivery (PD) input for charging. In that case, peripherals and displays can function through the dock while the laptop still will not charge. This matches the scenario because the dock and its power adapter are known good, and another laptop charges properly from the same dock.
- B. Incorrect.
Incorrect. External monitors connected to a dock do not normally draw laptop charging power in a way that would selectively prevent charging only one specific laptop while allowing another to charge from the same dock. The scenario points to a compatibility limitation on the affected laptop rather than a dock power-budget problem.
- C. Incorrect.
Incorrect. USB-A does not carry USB-C Power Delivery to charge a laptop through a dock. Using a USB-A to USB-C adapter would typically reduce functionality, not enable charging. This is a plausible misconception because users sometimes assume any USB adapter can pass all features, but dock charging depends on USB-C PD support end to end.
- D. Incorrect.
Incorrect. Laptop docking stations that connect over USB-C do not require Bluetooth pairing to provide charging. Bluetooth may be used by some peripherals, but it is unrelated to power delivery from a wired dock. This option reflects a misunderstanding between wireless device setup and physical dock functions.