Tempest two channel BeltStations have two different modes of operation. In Dual listen mode you hear both intercom channels A and B with individual volume control for each. You can also use one, the other, or both Talk buttons at the same time. This is similar to how the four channel BeltStations work now. In A or B Listen mode you hear either channel A or channel B one at a time, but not both. Pushing the appropriate knob button switches to that channel. No matter the application, Tempest two channel BeltStations work the way you do.