MyCap Junior Closed Captioning Device
There are three triangular buttons on the device. The left-most button is labeled "POWER." It is used to turn the device on and off.
The center button is labeled "CAPTION/TEXT." It toggles between the "Caption" mode and the "Text" mode. If you are in the caption mode, the leftmost red light will be lit, and if you are in text mode, the second light will be lit. Which option will use depends on the closed-captioning data on the media. From experience, most media seem to work best on the Caption setting.
The button on the right is the "L1/L2" button. This button allows for switching between different languages or sets of captions encoded on the media. Again, from experience, most media work best on L1.