CALL BACK / GET BACK TO (SOMEONE)
HANG UP
SWITCH OFF / TURN OFF
PICK UP
GET OFF (THE PHONE)
SPEAK UP
talk louder
stop talking on the phone
answer a call, lift the receiver to take a call
GET THROUGH
HOLD ON / HANG ON
put the receiver down
wait
to be connected to someone on the phone
deactivate (a mobile phone)
PUT (A CALL) THROUGH
return someone’s call
connect one caller to another