2N Helios IP User manual, 1510 v1.11 - Manual (Page 97)

Configuration 3.3
97
Hang-up by remote party – here replace the disconnect tone signalling that
the called station has hung up.
Busy tone – replace the standard busy tone.
Invalid input – replace the invalid lock switch password sound.
Invalid position – replace the speed dial button sound signalling a non-
programmed telephone directory position.
Lock switch activation – replace the lock switch activation sound.
Ringing – replace the standard incoming ringing tone when the Automatic
call answering function is off, refer to the Miscellaneous
subsection.