Our goal was to connect one of the 8-pin serial ports on the back on the
Macintosh to an RJ-45 connector. To do this, you need some kind of
adapter. We used an RJ-45-to-DB-25 adapter from Black Box Corporation; it
doesn't require solder. The DB-25 adapter can be connected to a DB-8-to-
DB-25 serial cable. Here are the Black Box part numbers:
* EVMAI: Apple II-to-ImageWriter cable (or use one of our cables)
* FA027: RS-232/RJ-45 modular kit, female
Note: Not all AT&T controllers are wired the same for RJ-45 connection, so
there is no guarantee that this exact wiring scheme will work for you.
However, it may give you a starting point. Follow these steps:
1) Test the wiring. (It's a good idea to use colors on the RJ-45 side to
avoid confusion). In this case, the following scheme worked:
RJ-45 pin DB-25 pin
--------- ---------
brown --------> 8
green --------> 2
black --------> 20
red --------> 3
2) Connect the pins on the RJ-45 connector directly to the pins of the
cable and attach a breakout box. You can monitor signals first at the
user site and make any necessary changes before you construct the
adapter. (Once the connections are plugged into the adapter, they're
hard to extract.)
3) When you've got the correct pinouts, construct the adapter accordingly
and screw it together.
4) Plug the cable into the back of the Macintosh, the adapter into the
cable, and the RJ-45 connection into the adapter for asynchronous access
to the AT&T. This works with MacTerminal and Red Ryder (two emulations
packages we use).