Is it the 19,200 bps modem, the IIgs or the Software?

[Rocket Press...a Litmag <rocketusa@delphi.com>]

Here's my latest mayhem. And, I'll state once again - this is the best
group on the Net... I've learned a ton already.
.
Okay, picked up a Galaxy Voyager v.32 turbo/v.42 19.2 kbps modem.
I set the control panel at 19200 baud. Use the generic 9600 bps
setting on Proterm 3.1. Played with the dip switches on the modem.
I have a Rom 01 GS with about 4 megs, sys 6.0.1.
 
When this modem flies, it flies, as compared to my internal 2400 bps.
But it seems unpredictible. It has a problem hanging up 99% of the
time. Even running it at 9600, though a bit more stable, leads
to problems.
 
My Proterm settings seem okay. I used the parameters Delphi
suggests for my modem speed. But I'll often freeze after a couple of
minutes online.
 
If anyone knows anything about this modem or Galaxy Networks or
problems with 19.2 and the IIgs let me know. Thank you!
.
PS - I've tried almost every other setting and every modem driver listed
in Proterm's file. I even tried it on a Mac Plus (though a step back from the
IIgs) - which had similar problems logging on and then staying on.
Could it be the cable?  Am I missing a dip switch setting?