Last updated: 01/18/2026
This article covers the following products:
- All Universal 2nd Gen
- All Universal DisplayPort
- All Modular SKVM
Overview
Video Switching Functionality
Video data flow comprises unidirectional Extended Display Identification Data (EDID) and video data flow paths.
The Secure KVM processes EDID through a 2-step process:
- EDID Read and Verification
- EDID Write
EDID Read Function:
For each display device, an EDID read event occurs only when the secure KVM is being powered up. The video controller MCU reads the EDID content from the display device to verify that it is valid and usable. If the EDID data is not valid, the secure KVM will not send data to the display peripheral.
EDID Write Function:
The video controller MCU (displayed in blue) writes the EDID data into the first channel of the emulated EDID Electrically Erasable Programmable Read-Only Memory (EEPROM) chip (shown in gray). The thick lines in the diagram below represent native video lines, while the thin lines represent Inter-Integrated Circuit (I2C) lines. The EDID multiplexer connects the I2C lines to the first EDID mode switch (shown in orange), which then switches the video controller's I2C lines to the first emulated EDID EEPROM chip (shown in gray).
The chip's write-protect switch opens to allow writing. The video controller uses the I2C lines to write to the first emulated EDID EEPROM chip. Once the write operation is complete and verified, the video controller closes the write-protect switch for that channel's EEPROM, ensuring that no connected host can manipulate the EDID file passing through the secure KVM. This process repeats on the first connection to each channel. Because this occurs during the initial channel connection, switching video rendering afterward may take 5–10 seconds, but subsequent switches should only take 1–2 seconds, as the described process would have already been completed.
NORMAL MODE
After the EDID write process completes for the affected channel, the secure KVM operates in normal mode, with each computer interface functioning independently. Power to each emulated EDID EEPROM is supplied from its respective computer through the video cable. The main video multiplexer switches to the user-selected computer to enable the proper video display. Any attempt by a connected computer to influence the EDID channel is blocked by the architecture.
Video input interfaces are isolated from each other. Isolation is accomplished by using separate power and ground planes, individual electronic components, and a dedicated emulated EDID chip for each channel.
