StarDestroyer.Net BBS

This awesome PSA from the 70's is super cool to watch. I love the retro-feel of all the electronics in the room and it kinda makes me think of Andor. It's driving me crazy but I can't figure out what C-3PO is working on in the beginning. It's a strange looking device and makes a bubbling sound. What could it be?

https://www.youtube.com/watch?v=oAsnzVSyznw