The S2-MTB6 is used to communicate with up to 6 other locations, studios or mixing desks, as well as with Sonifex TB-6D and TB-6R talkback intercom systems. When a button is pressed, the switch is illuminated and the talkback is active. The buttons work in both momentary and latching modes - if held down, the selection is cancelled upon release. Otherwise, the button operates in toggle mode.