220-1101 Question 210
Single answerUSB-CA user connects a new USB-C docking station to a laptop with a USB-C port. The dock's Ethernet and USB keyboard work, but the two external monitors connected to the dock remain blank. The dock is known to work with other laptops. Which of the following is the MOST likely cause?
- A
The laptop's USB-C port supports data only and does not support DisplayPort Alt Mode or Thunderbolt video output
- B
USB-C cables cannot carry video signals, so a separate HDMI cable must be connected from the laptop to the dock
- C
The dock requires a USB-A to USB-C adapter before it can output video correctly
- D
The laptop must be connected to Wi-Fi before the dock can initialize external display support
Show answer and explanation
Correct answer: A
Explanation
This question tests a key A+ Core 1 concept: USB-C ports are physically identical but may support different features. In real-world troubleshooting, technicians must verify whether a laptop's USB-C port supports DisplayPort Alt Mode or Thunderbolt when a dock is expected to drive external monitors. It is common for USB devices, Ethernet, and charging to work while video fails if the port is data-only. Best practice is to check the laptop manufacturer's specifications for USB-C capabilities, confirm the dock's video requirements, and verify that the cable in use supports the needed mode. USB-IF guidance and vendor documentation consistently distinguish the USB-C connector from optional capabilities such as alternate modes and Thunderbolt support.
- A. Correct.
Correct. USB-C describes the connector shape, not the capabilities of the port. Some USB-C ports support only USB data and charging, while others also support video through DisplayPort Alt Mode or Thunderbolt. If Ethernet and USB peripherals work through the dock but displays do not, the most likely issue is that the laptop's USB-C port does not support the video mode required by the dock.
- B. Incorrect.
Incorrect. USB-C can carry video when the port and cable support a video-capable mode such as DisplayPort Alt Mode or Thunderbolt. A separate HDMI cable from the laptop to the dock is not how a USB-C dock normally provides display output.
- C. Incorrect.
Incorrect. A USB-A to USB-C adapter would not add video capability. USB-A does not support USB-C alternate modes for display output, so using such an adapter would generally reduce functionality rather than enable monitor output.
- D. Incorrect.
Incorrect. External display support through a USB-C dock does not depend on Wi-Fi connectivity. Network access is unrelated to whether the USB-C port can pass video to the dock.