VoIP at last (Atlanta) NANOG?

Hate it when this happens... I'm having a conversation with someone about VoIP, and I am remembering something about the last NANOG where someone was talking about building VoIP gateways where they used DSPs to work directly with the digitally-encoded voice (PCM?) signal rather than the "normal" way. If anyone remembers this presentation (I may have been in an alternate reality at the time), could you remind me who gave it? Thanks. Pete.