An example [ahk](AutoHotkey v2) script that switches monitor input to another PC using DCC/CI, when the USB-only KVM switch switches from this PC.

I've got two PCs on my table and three Dell monitors (2x Dell U2412M and 1x Dell U4320Q). They are connected as follows:

• monitor1.USBC ← PC1
• monitor1.DisplayPort ← PC2
• monitor2.DisplayPort ← PC1
• monitor2.DVI ← PC2
• monitor3.DisplayPort ← PC1
• monitor3.DVI ← PC2

I've got a cheap "Unnlink KVM Switch USB 3.0 Model 0945" USB KVM, that allows to connect my mouse and keyboard to either PC1 or PC2 with a single click. However, it is unable to switch monitor inputs and (to my knowledge) got no API/software to monitor its state.

I hate manually switching monitor inputs with their hardware buttons (partly because they are awful). All 3 Dell monitors provide decent DCC/CI, allowing to control every monitor parameter without those buttons. However, Dell never bothered to release any software to actually utilize the DCC/CI capabilities of the Dell U2412M. The "Dell Display Manager 1.0" does not support U2412M (newer monitors are supported and thus DDM 2.0 command line could be used instead of direct DCC/CI).

When the USB switch connects to another PC, the corresponding "Generic USB Hub" disappears from the device tree in the Device Manager. The AutoHotkey allows to subscribe to that OS event.

The DCC/CI commands are sent using the Monitor-Configuration-Class.

Only the currently active monitor is able to use the DCC/CI commands, thus the same script should be started on both PCs.
The script would ask monitor to switch to another input when the specified USB device would be disconnected.

1. In Windows Device Manager, use "View -> Devices by connection" to see which specific USB devices disappears when USB switch disconnects. Copy "Device instance path" property value from the "Details" tab. Use it as the WATCHED_USB_DEVICE_ID value in Switch_monitor_input_on_KVM_disconnect_PC1.ahk.
2. Use ClickMonitor 7.2 "VCP codes" feature to view your monitor IDs, expected currently selected input ID and the available input IDs. Modify the Switch_monitor_input_on_KVM_disconnect_PC1.ahk accordingly.
   • Another option is to use softMCCS version 2.5.0.1093.
3. Same for another PC and Switch_monitor_input_on_KVM_disconnect_PC2.ahk