2300c internal modem question

[Paul Simons]

I own a 2300c. Question - I can never get the internal modem to 
connect in Powerbooks and Duos. What kind, speed, etc. of modem is 
in the 2300c? Any tricks or info on getting it to dial appreciated. I have 
turned off AppleTalk, set the PPP control panel to 'Internal', but still 
nothing. I've had the same with a PowerBook 540c, an external 
modem works fine, but not the internal. I wish I could just pick the 
right one from the list of modem drivers in the Modem control panel, 
for a start. Thanks, Paul