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Difficulty: MediumMobile Device Hardware and Display Issues

A user connects a high-resolution external display docking station to a newly issued mobile 2-in-1 convertible device using a Type-C cable. While USB peripherals connected to the dock function properly and the device receives power, no video signal is transmitted to the external monitor. The technician confirms that the docking station and monitor operate correctly when tested with other corporate laptops. Which of the following is the most likely cause of this display issue?

  1. The USB Type-C port on the 2-in-1 device supports standard data transfer and power delivery but does not support DisplayPort Alternate Mode or Thunderbolt protocols.Answer
  2. B
    Any device equipped with a physical USB Type-C connector automatically supports full Thunderbolt video passthrough, indicating the docking station firmware is corrupt.
  3. C
    The internal high-voltage backlight inverter board on the mobile device's screen has failed, disabling external monitor video passthrough.
  4. D
    The mobile device was upgraded with standard full-sized desktop DIMMs instead of SO-DIMM modules, restricting GPU display channel bandwidth.

Answer

The USB Type-C port on the 2-in-1 device supports standard data transfer and power delivery but does not support DisplayPort Alternate Mode or Thunderbolt protocols.
While the USB Type-C physical standard provides a universal connector shape, features such as DisplayPort Alternate Mode or Thunderbolt video signaling are optional hardware specifications. If a mobile device's USB-C port is limited to basic data and power delivery, external monitors connected to a dock will not receive a video signal even if USB peripherals and power charging work properly.

Step-by-Step Solution

1
Analyze the observed symptoms
USB data peripherals and charging function via the dock, but external display output fails.
Symptom isolation confirms basic USB signaling and power lines are operational.
2
Evaluate hardware capabilities and standards
The physical USB Type-C connector supports multiple optional features (Power Delivery, USB 3.2 data, DisplayPort Alt Mode, Thunderbolt), but implementation is optional per manufacturer design.
If the host device's Type-C port is not wired for DisplayPort Alt Mode or Thunderbolt, video output cannot be transmitted over the cable.
3
Formulate technical conclusion
Identify port capability limitation on the 2-in-1 mobile device as the root cause.
Because the dock and display function with other systems, the bottleneck is the specific host port feature set.

Key Concept

USB Type-C Capabilities vs. Alternate Mode & Thunderbolt Protocols
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Topics

Mobile Device Hardware and Display Issues

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