Toyota PRIUS Owner's Manual page 188

INFORMATION
In the following conditions, the sys-
tem may not function.
D
The cellular phone is turned off.
D
The current position is outside the
communication area.
D
The cellular phone is not connected.
D
The cellular phone has a low bat-
tery.
172
27p333
By pushing the telephone button above,
you can receive a call or hang up with-
out taking your hands off the steering
wheel.
27p334
You can use the microphone above
when talking on the phone.