Hard to tell if it's really a DG manual or something else.
Hard to tell much of anything on that site.
I do know other manufacturers were making Ham interface cards at the time.
I recall I did buy some manuals from Herb in the past (maybe late 20th
century) before I went all digital. Nice to see he's still around.
Overall, the DG system is progressing nicely.
I have the quad Phi-Deck, the Vortrax, and now the Ham card.
And the nice metal cases too, clean and unmarked.
-J