9 Wall Plate Issues

Basics

In many buildings, staff and students have to connect their devices to a display through a wall plate. There may be older wall plates in your building that may have limited connection options. A more recent development is the RapidRun AV wall plate that provides a variety of connection ports that are run through a single cable. RapidRun doesn't require terminating cables or plate ports so they don’t require tools, splicing, or soldering. Regardless of the type of wall plate in your building(s), when something goes wrong, people won’t be able to connect to your displays. 

This module addresses troubleshooting older wall plates. If you are looking at upgrading, you should look at 9.1 Replacing Wall Plate with Rapid Run Plates.

You should know the following terms:

  • Atmos
  • Firmware
  • HDCP (High Bandwidth Digital Copyright Protection)
  • HDMI
  • Latency
  • RaidRun AV wall plate
  • VGA
  • Wall plate

One of the most common issues with HDMI AV connections is no video displayed on a projector or an HDTV. To troubleshoot these connections, try the following:

  • Check to be sure all the devices are turned on.

  • Do a visual inspection of the cables and the wall plate. Is the plate or are the cables damaged?

  • Disconnect and reconnect your cables. The cables should fit snugly into the computer ports. You should lose connection when you wiggle the cable. 

  • While cables are disconnected, if there is a VGA plug involved, check the pins to be sure they are not bent. When reconnecting, make sure the VGA thumb screws are tightened. If a screw is missing, replace it. 

  • Is the projector or TV plugged into the correct input?

  • Is the cable plugged into the correct HDMI port on the display (projector, TV, monitor)? Some devices may only have one HDMI input that is capable of full bandwidth. If there are two ports, try plugging the cable into the other port to see if it works. Be sure to use the correct cable type. 

  • Verify that the cable works by using it in another room that is known to have a working pair of devices.

  • If you are using an HDMI adapter, is it functioning and providing a strong enough signal? A high-quality adapter is important. Loss of signal may easily occur when you have an adaptor of lesser quality. Try another adaptor or try your adaptor on a projector that you know works. 

  • Be sure your Windows output is set to the correct option. Press Windows+P to check.

  • If the cable, laptop/desktop device is working, check the AV wall plate. Be sure it has the correct type of cable. The current HDMI specification calls for cables to be between 2-10M (6.6-33ft). If you have a longer run, you may have to use an active HDMI cable. 

  • Check to be sure the ports are functional. You can do this by connecting the computing device with the same cables in a different wall plate.

  • Determine whether the software or firmware should be updated.

Other Things to Consider

Infrastructure issues can occur when a part of the system is incapable of handling a signal type being sent over HDMI. Symptoms of infrastructure issues can include: incompatible signal message, picture/audio drop, no picture, sparkles, and/or snow.

Consider the following steps to resolve infrastructure issues:

  • Ensure all HDMI cables and devices can support the signal being sent. For most use cases, a High-Speed HDMI Cable with Ethernet (Capable of 18Gbps) will be more than enough to satisfy signal transport if every device can handle said signal.

  • Ensure your HDMI cable is the correct length. The current HDMI specification calls for cables to be between 2-10M (6.6-33ft).  When going longer distances, it is recommended to use an Active HDMI Cable. 

  • Ensure you are in the correct input for your HDMI device. Some HDMI devices may only have one input that is capable of full bandwidth. This is usually stated in the device specification or user manual.

  • Check for software updates. Sometimes, critical software updates increase a device's capability and require installing before achieving a specific signal. https://www.belden.com/blogs/smart-building/cable-considerations-for-av-over-ip

  • Bandwidth (amount of data) is critical for video. With HDR 4K video signals requiring 18 Gb/s of uncompressed data, unless you run fiber or multiple category cables, you may have to compress the signal.

  • Latency refers to a delay in the signal. Most AV signals demand a constant stream of information, so delays can cause sync issues or signal loss. This can create problems, especially when you’re controlling interactive content or viewing a live performance where delays as small as 15 ms can be noticed. 

Issues with Settings. Settings are one of the most easily overlooked factors in the HDMI system. In today's world of so many different types of video signals, plug-and-play may not work. Check your settings, especially the display settings.

If you believe there are issues with the settings of your system, consider the following:

  • Ensure your device is in the correct mode. Many AV receiver and display manufacturers include an enhanced setting or mode that will change the input's signal capabilities--allowing for full 4K as well as HDR.

  • Ensure the source is set to output the correct signal. While you may get an image right away, some source devices are set to output a default resolution to guarantee at least some picture to show. Video output options are usually found in the advanced menu settings.

  • Ensure you have the audio playback device correctly configured for Atmos surround sound, if available. This often requires changing the speaker configuration settings beyond the standard 5.1 to 5.1.2 (or equivalent Surround.Sub.Atmos setup for your configuration).

  • If issues are still present after changing settings, you may need to power cycle the devices for changes to take effect or for other devices to see those changes.

Handshake Issues: Unlike previous analog signals, such as composite and component, HDMI requires a complex system of handshakes including one known as HDCP (High Bandwidth Digital Copyright Protection). These handshakes are required on every device in the HDMI system and can cause catastrophic signal failures if inappropriately handled. Common Handshake Issue symptoms include: incompatible signal image, black screen with audio, snow, green/purple overlay, or inconsistent video.

Use the following steps to troubleshoot handshake issues:

  • Ensure the cable length meets specification. Once again, cables outside of the HDMI specification may have consistent erroneous handshakes. This can be from the signal coming in too “hot”(the signal is at too high of an amplitude at short distances) or too “cold” (the signal is too weak at longer distance)..

  • Confirm the settings are correct using the tips provided. Like cabling, settings can also play a major impact on multiple issues. Because devices can send multiple formats of HDCP, a more advanced setting may allow a device to handle more advanced versions of HDCP.

  • Try installing a conversion device. Older devices may be incompatible with newer signal types and require a conversion device to work correctly, especially in a distributed system. A scaler device and/or HDCP conversion piece may be required for your display to accept signals from a source it is incompatible with.

Information Credits: 

Here are additional resources you may find useful:

Complete the following task or self-assessment:

Be sure you know how many wall plates you have in your building(s) and where they are located. If they are not already documented, add them to your Systems Overview Data spreadsheet. 

  • How many wall plates do you have in your building that are not functioning? Add this content to the data you are collecting.