Diane Keaton was taken away from her Los Angeles-area home Saturday by ambulance and died … and the dispatch audio to the fire department reveals a “person down.”

TMZ obtained the 911 audio from the call to service at Diane’s house and you hear “Rescue 19, person down” before the dispatcher says her address.

As we reported … LAFD says they went to Diane’s home at 8:08 AM Saturday and an ambulance took one person to a local hospital.

Our sources told us the person in the ambulance was Diane.