Adapt Sound will now run a hearing test, which consists of a series of beeps of varying frequencies from the left and right earbuds. (android.gadgethacks.com)
Some cars sound warning beeps when your car crosses a solid or dotted lane marking, then silences itself once it's away from the lane edge. (extremetech.com)
From the 3rd to 7th time the collar start with beeping sound follows by the vibration. (petpeoplesplace.com)