IIgs builtin serial and a Performa Modem Project

[Port <mlafranc@tfz.net>]

There was no mention of this in the CSA Serial/Modem FAQ, So here goes

I have a Global Village Communication TelePort Gold II designed for a
Macintosh Performa.  It was used on a PowerMac that has a deceivingly
(dis)similar serial port.

(Display in fixed width font)

Macintosh Port:         IIgs Port:

-        ---------            ---------
-      /___________\        /           \
-      |           |        |           |
-      |   1 2 3   |        |   1 2 3   |
-      |  4 * 5 6  |        |  4  5  6  |
-      \    7  8   /        \    7  8   /
-        ~       ~            ~       ~ 
-          -----                -----
        Mini-Din 9           Mini-Din 8

There are four pins in the middle with this port, I guess you would
call it Male Mini-Din 9, anyhow, the fancy thing about this modem,
beside the fact that it's a good bid faster than what was out at the
time, It has no power supply, kind of like a USB? or certainly a
PCMCIA modem.  Just the serial cord and a Line-In and a Line-Out.

So... I'm taken to believe this little extra pin, I spelled out as the
* (the other pins line up) is a +3 or +5 V supply, although I really
have no idea.

What if any measures could I take to have this modem working on my Woz
IIgs.  I'd probably have to intercept this wire after the Modem cord
Jack-Head with an adapter and send the relevant serial lines off to
the IIgs.  I doubt I'll ever find the material with which to do this,
so, I think I'll end up splicing into the Modem cord itself and using
the Male Jack-Head to plug into the IIgs, this means:

Shave into the IIgs Jack, you see Apple must have specified that a bar
be put on the top of the Cord End, as I tried to illustrate and break
off the extra pin...

Then, run a ?V tap from somewhere on the motherboard out through one
of the card bays... I haven't ripped into the thing too much.  I'd
like to keep the IIgs as visually original as possible... I don't care
about monkey-work, as long as it's done well.  Run the tap through a
mini-phono jack or something mounted to the plastic card-slot guard
and you've got an easy plug 'n play low-power modem.

So, I need a couple of things, comments, suggestions, maybe an
informed person to tell me what services the pins on my modem cord
provide, just so I know for certain that I'm not going to snip a CTS
pin or something!

A guess as to where would be a good place to tie into the IIgs power
supply and what voltage this would have to be... and I should be able
to work this.

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