Most multi-switches do more then 2 ird's that is the whole point point of having them other then combining 2 or 3 birds. If an LNB was locked on one voltage you would only get half the channels. High and low voltage switch between the odd an even transponders. A 22khz tone switches the sats when you have 2 birds hooked up to one multiswitch. I have 2 powered ones in my home using powered pass-throughs and you can hear them clicking all the time switching voltages.