Yes funked you are right.
The Orange/White box sits by the side of the track and there is an IR transmitter in the car which must be aimed out of the window. The box is connected to an iOS device (iPhone, iPad or iPod Touch) by bluetooth.
All of the timing is handled by the iPhone in my case.
When you are on the rostrum, sliding the "Auto" slider prompts you to connect to your box which happens almost instantly. Once connected, the car passing the box start the timer. Each lap time is called by Siri from your iDevice, I prefer to use earphones but it will also work on loudspeaker if you prefer.
You can set your phone to vibrate to indicate the start of the run and vibrate to finish, there is also an option for Siri to call how many minutes you are into your run. The app also announces when you are on your last lap.
When you pass the box for your last lap the app announces a summary e.g. "Eighteen laps in three hundred and six seconds, your fastest lap was sixteen point six four seconds".
You then have the option to save the lap time data from that run, pressing save brings up a screen where you can input the name of the track and attach notes which are reviewable later. (I document setup changes made and any other information I feel was relevant to the run. You can see this any time under the history button in the app.
I hope you find this information useful and it clears up some questions.