So basically an assistant. How a developer can afford an assistant?
Is this an emergency? Interrupt them. Is this a minor inconvenience? Could this be talked about in the daily tomorrow morning? Is it something that someone else should actually know about? Block the information from the devs and deal with it in the chosen way.
Edit: to answer your question about affording one, it seems around 5 developers can share one secretary, and split the cost. Incidentally, this is a usual setup with a PM as well, but again, they often seem to think their job is to manage the developers, not the project (which they also often don't do).