What are the commands to switch a VMIX input On and Off?

You need to connect to the Engine on TCP port 4010. When the connection is opened send the login command:
LOGIN UNIT USER="user",PWD="yourenginepassword"

Then use the following commands to control the VMIX:
SET VMIX.SUB#2.IN#1 State=OFF
SET VMIX.SUB#2.IN#1 State=ON



What are the custom channel numbers to send from PathFinder to perform special functions on Uk Elements?

Channel 32002: Controls the on-air state of the console.

Channel 32003: Controls the Element External Preview audio input, for routing inbound talkback to the preview bus.

Channel 32004: Activate when sending talkback from the Element, causes CR speakers to be dimmed and Talk lamp to activate.