IIgs + High Speed Modem?

[rdippold@qualcomm.com (Ron "Asbestos" Dippold)]

So I finally get a hard drive, set up the IIgs next to the PC, get
ready to start downloading System 6...

I took my ZyXEL U-1496E from the PC, bought a "Mac+ to Hayes Modem, 5
Wire, Mini8 Male/DB25 Male" cable, and plugged that into the IIgs
Modem port and the ZyXEL.  Boot up good old ProTerm 2.1 (I'll have to
upgrade), and nothing will talk to the modem.

Control Panel Slot 2 is set to "Modem," all items under "Modem Port"
are set to defaults.  I told ProTerm to use the IIgs Modem port at
19200 and 2400 bps (why push it?).  No go.  Neither AWGS 1.1 or the AE
term program work.  Brought it back over to the PC just in case I
smoked something, but no problem.  Also tried a Practical peripherals
28.8 modem on the IIgs, same problems.

Questions: Do I have the right cable?  I'm going to try another one,
but... Is this a known problem when talking to high speed modems (I
never had anything higher than 2400 on the IIgs)?
-- 
There is something going on now in Mexico that I happen to think is cruelty
to animals.  What I'm talking about, of course, is cat juggling.
  -- Steve Martin