The Auto Answer Switch is located on the back of the charging base to the right of the phone cord connection (pictured at right). CS510/520/540 RED = AUTO ANSWER OFF (Press headset button to turn headset on / answer a call) GREEN = AUTO ANSWER ON (Lifting headset from the base will automatically turn it on) CS530 Grey = AUTO ANSWER ON (Lifting headset from the base will automatically turn it on) Black = AUTO ANSWER OFF (Press headset button to turn headset on / answer a call) *Position of button is the same on all 4 units but the color is different on the CS530. NOTE: After turning this feature on, you may need to reconnect the power cord to the base for Auto Answer to work.