Hi Claude, it's been a long time since I heard the word Multiscan
. There is no pdf, in fact I wonder if that format even existed in the time I designed that modem. I think the original documentation is made with WordPerfect.. I no longer have any of those files at hand, maybe somewhere on a floppy disk in a dusty archive! I thought I still had it on paper somewhere but cannot find it either. Keep in mind the design is probably 20+ year old and was later replaced with the (better) DSP. Ironically enough I still have spare parts and even pcbs.
However, leave it up to certain individuals to show no respect for my copyright and publish my work on the internet et voila: here is the schematic and DIN pin configuration: