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CATX1000: Learning the EDID

This article covers the AVX1008 and AVX1016 also known collectively as the CATX1000. The IP version of the CATX1000 series, the AVX1008IP and AVX1016IP does not support this feature.


The CATxIP1000 (AVX1008IP and AVX1016IP) uses a pre-defined built-in EDID. The maximum supported screen resolution is 1600x1200.

Unlike digital video interfaces, analogue interfaces like VGA do not detect when the monitor has been changed.  They typically only detect the monitor and read the EDID on boot.  Therefore, a reboot would be required to ensure that the host is reading the expected EDID.  There are of course exceptions, particularly on some laptops where they do detect the presence of an external monitor.

Out of the box, each CATX-Module has a built-in EDID that supports a default set of resolutions. When the host computer boots, it reads the EDID directly from the CATX-Module, which determines which resolutions are available on its operating system.

To update the CATX-CAM Module with the actual monitors EDID, which may offer different resolutions, the monitor, CATX1000 (AVX1008/AVX1016), CATX-CAM Module and host need to be switched on in a particular order to pass the EDID down the chain. The following instructions assume that the cables are physically connected between each of the components.


  1. Disconnect the Power cord from the host computer
  2. Connect the Monitor to the local VGA port of the CATX1000.
  3. Connect the CATX-CAM to the host computer and CATX1000.
  4. Power on the Monitor
  5. Power on the CATX1000.
  6. The CATX1000 will read the EDID from the Monitor.
  7. Power on the host computer.
  8. The host computer will, in turn, provide power to the CATX-CAM Module, either via the PS/2 connection or USB depending on the model.
  9. The CATX-CAM Module will read the EDID from the CATX1000 and store it locally.
  10. The host computer will then read the EDID directly from the CATX-Module.

Further Information

  • Some host computers will power the CATX-Module whilst in standby. Check the CATX-Modules link lights to make sure that they are off until the host computer is powered on. If you do find that the CATX-Module link lights are on when the host is in standby, you will need to re-connect the CATX module from the host when performing step 7 above. You may also need to reboot the host afterwards if the available resolutions for the monitor have not changed.
  • By default, the CATX switch will read the monitors EDID on power up. If you do not want the learned EDID to change, you can change this option through the local OSD menu.
    • Open the OSD menu, press and hold CTRL+ALT+M
    • Press F1 to enter the Configuration Menu.
    • Press F1 again to enter the Advanced Options
    • From the menu, choose DDC Options

    There are two options for DDC Refresh, AT START and DISABLED. The default setting is AT START. If you change the setting to DISABLED, it will not update the learned EDID on power up.

Page last modified on Thursday July 8, 2021 10:42:01 GMT-0000