TOYOTA 2012 Avalon - Manual (Page 304)

324
3-4. Using the hands-free system (for cellular phone)
■
Call history
Up to 5 numbers can be stored in each of the outgoing and incoming history
memories.
■
When talking on the phone
●
Do not talk simultaneously with the other party.
●
Keep the volume of the receiving voice down. Otherwise, voice echo will
increase.