[G4] Apple Ext modem stops with OS Upgrade?

[John Erdman]

I just ran into a curious problem.   All of a sudden my dial up  
connection with the Apple External modem won't handshake.  The modem  
dials correctly to my ISP.   The handshake process starts but before  
I get a connection the sound deteriorates to what sounds like the  
needle skipping on an old LP record.  It never gets as far as trying  
to authenticate the user. Internet Connect freezes up for about a  
minute then it takes forever ( about 5 minutes) for it to disconnect,  
never having made a handshake.

It's curious in that the dial up system worked quite well until  
recently. I *think* it may be related to the recent upgrade I made  
from 10.4.6 up to 10.4.9.  but I can't find any Apple articles  
reporting any such problems.

The same same thing happens when I use alternative access numbers.  
Also no storms that mght have compromised the modem. It's acting like  
somethiongs amiss in the handshake process.  Are there any prefs that  
might be corrupted.

Any ideas for what has happened or what to try?

Thanks

John Erdman
Hardware: G4-AGP 400MHz, 1.2 GB memory, Mac OS 10.4.9