recent voice over data

the great voice-over-data protocols and products introduced by Intel, Rockwell, ZyXEL and others at Comdex which will make Voice-PGP so much easier As I understand these voice-over-data products, the voice goes over analog, added to the modem signal. The modem signal is interpreted, and then reconstructed and subtracted from the incoming signal, leaving voice. Very clever, but insufficient for secure phones. Eric