VTA is a system that enables VoIP Telephony operator to see a current state of calls, both - successful and failed. Information about traffic is generated in off-line mode. That means balance is calculated after a call termination. If any of the conditions are broken, then a system reacts according to the specified settings. If a balance of an operator-partner is lower than the allowed limit, VTA blocks access from operator-partner's IP address. For the calculations VTA is using information about call based on data that is received from VoIP gateway: On call duration and call direction (incoming or outgoing) Time and date of call IP address of a gateway You need to have VTA if: You want to know the balance at any time You work with operator who might "forget" to make a payment for an existing dept You want to manage your resources with ease and precision You need to have a clear picture of your finances You favor systematic approach in running your business