Modem not found

[Sean Collins]

I'm having no luck getting an internal modem to work, hoping someone 
can clue me in to the trick.

System is a G4/AGP, bought new years ago w/out internal modem.  I've 
been using a GeeThree Stealth serial card w/external modem & other 
RS232 devices all these years w/out problems.  Due to system changes, 
I no longer needed the Stealh serial port, so I decided to install an 
internal modem.  I've been unable to get the G4 to recognize the 
modem.

The modem is known good:  when I put it in my Lombard G3 it works 
fine. The I/O port on the G4 is known good:  when I reinstall the 
Stealth card, it works fine.  But when the modem is installed in the 
G4, it's no-go.

I've done all the usual things: rebuilt desktops, reset the Cuda 
switch, zapped PRAM, deleted preferences, etc.

Using a spare disk drive:

Clean install of 9.2.1 - no modem recognized by System Profiler
Clean install of 10.2.8 - no modem recognized by System Profiler
Clean install of 10.3.2 - a modem is recognized as a "v.90" device, 
and "com.apple.driver.AppleSCCSerial (v1.2.6)" driver.

In the Network preference, 10.3.2 notices a "new serial port", and I 
can configure it w/ "Apple internal 56k modem (v.90)", but when I try 
to USE it, it doesn't work.  No response from modem, no off-hook, no 
dial-tone, no dial-out, etc., and internet connect finally times-out.

What am I missing, Is there a trick to this?