Lexus LS460 2011 Owner's Manual page 552

3-5. Using the hands-free system (for cellular phone)
Status display
You can check such indicators as signal strength and battery charge
on the "Telephone" screen.
Indicators
Connection status
Battery charge
Call area
Signal strength
520
LS460_EE
Connection status
Battery charge
Call area
Signal strength
Conditions
Blue: Good
Yellow: Bad
: Not connected
Full
"Rm": Roaming area
"Hm": Home area
Excellent
Empty
Too bad