Toyota 2015 Prius Owner's Manual page 324

Status display
You can check indicators such as signal strength and battery charge
on the phone screen.
1
Connection status
2
Signal strength
"Rm" is displayed when receiving
in a roaming area. While roaming,
display "Rm" top-left on the icon.
3
Battery charge
Indicators
Connection status
Signal strength
Battery charge
PRIUS v_OM_OM47887U_(U)
5-9. Bluetooth
Conditions
Good Poor
Excellent
Full
I n f o r ma t i o n P r o v i d e d b y :
323
®
phone
Not connected
Poor
5
Empty