If someone already did work with the S&S Speech synth, help is always welcome..
for the interface, i think it is this website. : http://sites.google.com/site/analogvocoderinfo/speak-spellI've taken a lot of info from there.
as i know in the S&S, it is a TMS5100, which is quite different.
I know that it is now a collector, but sometime you can find cheap ones on ebay.