(Ahhh
TLA overload is fun isn't it?)
NAS is known, to some, as the Network Audio System. NAS was developed by NCD, the makers of some really kick ass X Terminals.
From the NCD sample implementation release notes (version 1.2p4):
an audio protocol for networks...for playing, recording, and manipulating audio data over a network. Like the X Window System, it uses the client/server model to separate application code from the specific drivers needed to control audio input and output devices attached to the X terminal or workstation.
I must admit to never having seen it in use. I found it when playing with X terminals, and that was it. It apears to have never really caught on for anything except piping sound to X terminals.