I love a challenge, and boy is this a good one. The www.ab.com site has nothing but references to the 1771-AS as far as compatibility with other adapters and which resisters should be used. AB tech help only knew that it comes from the old PLC2 days but is still compatible with PLC5's if 2-slot addressing is used. They told me to call 800-NEWLIT which is supposed to be the last hope for documentation and they had nothing. It was fun hunting, but I am sorry to say I could not find anything either. You appear to have an undocumented dinosaur on you hands.
I found an old manual for the 1771-AS module. Pub.# 1771-938 Dated March 1984. P/N 955095-80. I don't see any 9 Pin connector on it and there is
no mention of it it the manual. Send me your fax # if you like and I'll send it to you. ( I didn't see the beginning of this thread)