After initially pairing your mobile device to the Pulse Link via Bluetooth and setting the audio source to “3.5mm Line in” via the Pulse app, it is not necessary to keep your phone connected via Bluetooth to the Pulse Link.
Your TV/Computer/CD Player can output sound to the Pulse Link without requiring your mobile device or the Pulse App to be open, as long as the Pulse Link has been set up correctly.
If you wanted to control the LED of the Pulse Satellites on the Pulse Link, you would have to use the Pulse app.