If the number you are calling is repeatedly busy, you can activate Repeat Dial that automatically re-dials the number until it is reached. To activate Repeat Dial, hang up the phone after the first time you hear a busy signal for the number you dialed. Pick up the receiver again and dial *66. After the recording tells you Repeat Dialing is activated, hang up. As Repeat Dialing keeps calling, you can still use your phone as usual. A distinctive ring means the line you are redialing is free. Pick up, and the number you want will be ringing. If you hear a fast busy signal or an announcement that the call cannot be completed, then the number is either invalid/not working, or has activated Call Forwarding.