The video traffic director is an UltraAV Mini HDMI Splitter from Accell, a company that makes a variety of cables and digital signal devices. The takes an HDMI signal from a computer, DVD player or other sources and shares it with multiple display devices. In my case, I'm using the Accell splitter that supports up to four external displays. That model costs about $100. Accell makes other splitters that support more or fewer displays.
A row of lights on the front of the splitter shows how many cables are connected and in use, but there are no switches to individually turn an output on or off. In my setup, the splitter also reset the display resolution, making text a little less sharp. Fortunately, I don't plan to be doing any word processing or spreadsheet work on the big screen. For browsing the web or watching videos, the Accell splitter delivers everything I expected.