An HDMI Switch, also known as an HDMI audio/video switcher, is a highly practical device that allows you to easily switch multiple HDMI interface input sources. With an HDMI switch, different images can be output on the same screen without the hassle of constantly plugging and unplugging HDMI cables.

Whether you’re gaming, using a Nintendo Switch, or steaming from a set-top box, you can seamlessly switch to the corresponding input source with just a press. This versatility allows HDMI Switches to provide an extremely practical solution for multimedia needs, ensuring a smooth and diverse home entertainment experience.

HDMI Switch connection diagram


Potential Risks:

Although HDMI Switches have the capability to handle multiple HDMI interface devices simultaneously, some models may encounter issues where the screen fails to display images properly after switching between different input sources, leading to consumer complaints. This situation may involve specific brands or models of HDMI switches experiencing compatibility problems during certain signal conversions or switching operations.

Real-life Examples:

Allion has dealt with numerous HDMI Switch manufacturers seeking solutions due to consumer complaint issues. This article will share two common scenarios.

Scenario 1

Consumers experience mismatched resolutions between input sources and displays after switching between different input sources. Upon measurement and verification, it was found that this HDMI Switch model lacks a dedicated HPD pin. Without this design, the Switch only outputs at the minimum 1080p resolution when receiving 1080p, 2K, or 4K signals. However, if there is a dedicated HPD pin, the output signal will be based on the resolution of the input signal rather than the lowest resolution of the input source.

HDMI Switch two common scenarios

Scenario 2

Consumers encounter situations where the screen either fails to display images or displays images with mismatched resolutions after switching between different input sources. Although similar to the previous case, it was found through verification and analysis that the issue stems from the HDMI Switch’s EDID. The EDID of this model does not support the resolutions of the input ports used by consumers. Regularly updating the supported EDID table by the manufacturer can resolve such issues.

Faster, Easier, Better!

Allion is an HDMI certification laboratory with extensive project experience. In addition to providing a full range of certification services, we also offer related engineering verification consulting services. Our services have the following three major advantages:


Allion possesses complete HDMI verification equipment and environment, including oscilloscopes, signal generators required for electrical signal verification, protocol analyzers for protocol analysis, and EDID simulators and controllers related to EDID.

HDMI Testing equipment

Allion also has a large number of various types of HDMI devices, providing compatibility verification services to ensure the best quality for your product.


Having executed numerous certification projects, Allion has accumulated rich debugging experience. We can provide consulting services for problem analysis and debugging support. With our experience and the use of various types of instruments, we can quickly analyze and identify the root cause of issues.


After identifying the cause of the problem, Allion can promptly provide recommendations for problem-solving based on rich experience, allowing customers to rectify issues in the shortest time possible and get their products to market after verification, seizing market opportunities.


If you have any requirements or questions, please contact us.