Page "Macintosh Quadra" Paragraph 4

In 1993 the Quadra AV series was released, consisting of the 800-series Quadra 840AV and the 600-series Quadra 660AV, at 40 MHz and 25 MHz respectively.

Both included an AT & T Digital signal processor and S-Video and composite video input and output ports for video, as well as CD-quality microphone and audio output ports.

The AV models also introduced PlainTalk, consisting of the text-to-speech software MacinTalk Pro and speech control ( although not dictation ).

However all of these features were poorly supported in software, and DSP was not installed in later AV Macs.