A computer-implemented method and apparatus verifies integrity of a Voice over Internet Protocol (VoIP) virtual connection at an analog terminal adapter (ATA) at an edge of an Internet Protocol (IP) network. A VoIP transaction is initiated toward a cooperating test unit across the IP network, establishing a VoIP virtual circuit. The test unit responds by transmitting a digital representation of or information representing a test tone across the IP network to the ATA. By evaluating the test tone at the ATA, integrity of a bearer channel of the virtual circuit can be verified directly, and integrity of a signaling channel of the virtual circuit can be verified indirectly.