Blackmagic Design GPI & Tally interface (BMD-SWTALGPI8). Blackmagic Design GPI and Tally interface provides 8 contact closure inputs and 8 contact closure outputs for connecting to ATEM switchers and VideoHub routers. Tallies wil be displayed when connected to an ATEM switcher to indicate their "on-air" status and you can even connect multiple interfaces together to increase the number of inputs and outputs. GPI and Tally Interface also works as a VideoHub control panel without buttons and LEDs so you can make your own!