You can set the parent unit to beep when the link between the parent unit and the baby unit is lost.
To turn on or off lost link alert:
- Press
on the parent unit. - Press
or 
to highlight 
(Alert settings), then press . - Press
or 
to highlight 
(Alert tone), then press . - Press or to highlight
(Lost link alert), then press . - Press to toggle between
and 
.