On Wed, 14 Jul 1999, Ken Nakata wrote:

> http://www.itt-sc.de/pages/product_documentation/multimedia/asc.html
> 
> It says ASC 3553O, but it is the Singer chip.  It's ASC 3553O instead
> of ASCO 2300 only because they've changed the IC type designation from
> ASCO 2300 to ASC 3553O!
> 
> BTW, Apple's _Quadra 840AV and Centris 660AV Developer Note_ says, at
> page 16:
> 
> 	The Singer is an I/O chip that constitues a 16-bit digital
> 	sound codec.  It conforms to the IT&T ASCO 2300 Audio-Stereo
> 	Codec Specifications. ...

Cool. Thanks

What I got out of the Reference Guide for xxxAV macs is that the codec
has four channels, only one of which is used by the DSP, the others
being available for applications. I'm hoping to be able to use one of
those channels to fashion a back-end driver for /dev/audio.