Fiio R7 Manual page 10

Instructions for entry-level functions
1.Seven working modes
The R7 has 7 independent working modes: Android mode, Pure Music mode,
Bluetooth Receiving mode, USB DAC mode, Airplay mode, COAX mode and
OPT mode.
It is defaulted to enter Android mode when it powers on for the first time. You
can switch to other operating modes by holding the power button for about 2s
or dropping down the menu from the status bar.
If the player is in other modes but not the Android mode, you can switch it to
other modes through the selection on the display, or tap Settings->Exit to go
back to Android mode.