[Orgmode] Is it any function similar to appoinment alert in the planner mode?

[brianjiang]

I have just switched from Planner to Org recent and I find the Org mode
fit my need more.  But I failed to find a function that I used a lot in
the Planner mode. The function is that a alert window is pop up (with a
beep as well) when an appointment time is coming with in a few minutes.
Is it such a function in current Org mode. If no, can we implement it?
Thanks.

Regards,
Brian