Hopefully an easier answer to your pwr sense.... Unless you are using multiple controls in your system (ie:rp6 with a niles whole house music system / russound cav6.6, etc., and both systems are running and sensing the same equipment), i have found the flags in the programming to be very reliable. Create a flag named pwr on, use "flag test" anytime you want to power the system on or off, and set or clear the "pwr on flag" accordingly. I've been doin this on any stand-alone rti control system for a couple of years, saving money and hook up time, and haven't had any issues. Just warn the customer if they pwr things on manually, they will have to pwr them off manually to restore the "pwr sync" of the system to the programming. Most customers won't pwr things on manually if the remote works and will figure it out on their own if the pwr doesn't come on when the try to turn their system on.