Alt Mode video works by creating a direct pipeline from the host device's graphics processor through USB-C to the dock to output video to connected displays. This relies on the host device's graphics processor, the host device's USB-C port, and the cable used to connect the dock supporting this specific functionality.
It's recommended to check these possible causes if the Alt Mode video output on your dock is not working:
- USB-C Port Limitations: Not all USB-C ports support video output (Alt Mode). Check your host device's specifications to confirm it supports Alt Mode video output.
- Incompatible USB-C Cable: Some USB-C cables support power and data, but not Alt Mode video. Use the USB-C cable that was originally included in the box with your dock to ensure it supports Alt Mode video output.
- Incorrect Host Connection: Ensure you’re connecting to the correct USB-C port on the dock, typically labeled a laptop icon. Other USB-C ports on the dock may not function for connecting the dock to a host device, and using them could result in no function.
- Outdated Drivers: Ensure your operating system and graphics drivers are up to date. USB-C Alt Mode primarily relies on the laptops graphics processor to produce video, so outdated drivers can often cause issues.
Why the Alt Mode Video Output Requires Specific Hardware
For many Plugable docking stations that utilize Alt Mode, the video output port is etched with "Alt Mode" to indicate this specific requirement. This connection type is not a standard USB data stream and requires the host laptop's USB-C port to be wired internally for DisplayPort Alternate Mode.
Workaround or Alternative Options
If your laptop does not support Alt Mode, consider using a DisplayLink docking station or USB graphics adapters to add additional monitors. These solutions use a driver-based approach that does not rely on the host's physical Alt Mode capabilities.
Applicable To
UD-768PDZ, UDS-7IN1, UD-CUBE, UD-CAM, UD-CA1A, UD-MSTHDC, UD-MSTH2, UD-6950PDZ, UD-ULTC4K, UD-ULTCDL, UD-3900PDZ, UD-3900PDH, UD-3900C4, UD-4VPD, TBT3-UDZ, TBT3-UDC3, UD-7400PD, TBT4-UDX1, TBT4-UD5, TBT-UDM, TBT3-UDT3, TBT-6950PD, TBT4-UDZ
