This will be a test setup made with some discarded graphics cards and extenders. We first let the signal through without interruption for 150ms to facilitate communication for the monitor and GPU, which tells the computer what it is and how it should interact with certain aspects of the hardware.

Then, we wait until the signal stabilizes. The moment the HPD signal from the monitor goes down (which would be 3.3V > x > 2.7V), the device intercepts this signal and replaces it with its own 3.3V logic signal (with a 5mA current limit)

When the signal comes back, it immediately hands it back to the monitor (this may change -- may require the AUX lines to be held high at the same time to suppress double communication)