Rosen In-Dash Multi-Media System Owner's Manual page 43

Function
This function is available only when connected with GPS module.
2.81 Enter/Exit
Touch to enter navigation main interface.
While in navigation status, press NAV button on the panel to exit from navigation
status and return to other playing state.
2. 82 Music During Navigation
While in navigation mode, you can still listen to music. Voice navigation will interrupt
music when necessary.
To adjust the volume of voice navigation, adjust when there
IS
vOice
commands present.
For more detail on navigation functions, refer to navigation manual.