The IW I has I think a relatively standard serial interface but you
need a NULL MODEM as well as DB-25 to Mac serial cable
to run it from the later Macs. A null modem is simply a DB-25 pair of
connectors (male and female) that reverse all the lines. I think
my WEb page describes this in my cabling section. The lines to reverse
are 2 &3, 4 &5, 6 & 20. Pin 7 is wired to pin 7. That is line 2 is wired
to 3, and 3 to 2; and so on.

The dip switch settings should be set as follows (says the Dead Mac Scrolls)
The switch with 8 switches, they should all be set to "open". The switch
with four switches, set 1 2 3 to "open", and 4 the other way.

The Dead Mac Scrolls says something about the wiring from the mini8 connector
to the DB-25 connector:

        mac end (mini8)         DB-25 at Printer
        2                       20
        3                       3
        4                       7
        5                       2
        8                       7
        connector metal         connector metal