squawk box
squawker
intercom speaker

I heard his voice over the squawk box down the line.

He identified himself to the voice on the squawk box and was let in.

And I don't want two more squawk boxes turned on.

They were quiet the rest of the way, the only sounds being those that came over the squawk box.

He clicked off the squawk box and went back to work.

We've got everything on it - light, radio, even the squawk box.

Then the guy with the squawk box came back on and I agreed to the money.

A few seconds later, a voice sounding out of breath, came over his squawk box.

Without the squawk box his voice had an instantly intimate quality.

After the launch was complete, he called down to Combat on the squawk box.