A supervisory signal returned from the called telephone to the originating switch when the call receiver answers. Note 1: The answer signal stops the ringback signal from being returned to the caller. Note 2: The answer signal is returned by means of a closed loop. 2. An off-hook signal transmitted towards the network when the called party answers. 3. An off-hook signal transmitted towards the network to indicate when the customer installation (CI) equipment has changed to the communication state.