Card set identification

["David C Chiu" <none@nowhere.org>]

I got a rather odd set of boards which I can't make heads and tail of; it is
a three boards; appears to have been manufactured by Sequential Systems. The
"primary board" (full length) has a four position DIP switch and a daughter
card attached to it with Z80 and Z0853004PSC (I think this is an UART) with
a DB25 female hanging off the daughter card. The primary board has
additional five headers labeled A,B,C,D and P. Header A is connected to a
third board via a ribbon cable. The third board has two 8 position DIP
switches, labeled SW1 and SW2S, and contains a couple PALs and a EPROM
(QP11-1090B)

I do post the pics if I have some place to park those images, but since I
don't...