The HDMI switcher itself does not have an infrared receiver built into it. You must use the infrared receiver that you plug into the side. Since it is not a radio frequency device, the remote and receiver must have a clear line of sight to work.
Are you asking whether this switcher will work on all of your equipment or if it will work without AC power? If it's the former, then yes. Otherwise, the answer is that the switcher WILL work without AC power but you will have to switch it manually. As soon as you plug in the IR receiver, you require additional power.
What this essentially does is give you a total of (5) HDMI inputs for one output and the ability to switch remotely between them with the provided remote. I needed one because my Samsung HDTV only came with two ports which left me needing several additional ones to accommodate components. Great deal for the price......
I don't have direct TV so I'm not sure what it uses for the connection. If it uses an HDMI connection, then yes, you can use this device to connect them to your TV. I connect my xbox 360, blueray, and computer to our TV using this device. It only takes one HDMI input on our TV doing it that way.