A2Billing can authenticate calls in a number of ways:-
- VoIP registration – the endpoint is registered to A2Billing with a username and password.
- IP Address – All calls accepted from a specific IP address.
- PIN Authentication – Using a unique PIN code.
- Caller ID authentication – Using the CID for authentication. (Pinless dialling)
When a call comes into A2Billing, the customer is recognised using one of the above methods. From their identity, we know the amount of credit available for that customer.
The customer's dialled digits are captured, and from the rate tables pertaining to that particular customer, we know the rate for the destination.
By dividing the available balance by the cost per minute of the call, the total maximum duration of the call can be calculated. A “Dial” command is sent to Asterisk with the total time allowed for the call.
At the end of the call, which is either forcibly disconnected by Asterisk or when either party hangs up, the actual cost of the call is calculated, and the customer's balance decremented.
A2Billing has a very flexible billing system including connection and disconnection charges and stepped billing.