, I mentioned a soon-to-be-released update to the modem drivers for the PowerBook 3400. It is most especially supposed to address the problem where you cannot reconnect after a disconnect. I have been using a final candidate version of the drivers since Friday and have not had one reconnect problem since installing them. It is definitely working so far. Unfortunately, it appears to have had no effect on other issues regarding the 3400 modem, such as its slower than expected connect speed.
Meanwhile, D.J. LaChapelle writes that he worked around the reconnect problem by unplugging the phone cord from the back of the PowerBook." After about 20 seconds you'll get OT/PPP dialog box that says you've been disconnected, at which time you can plug back in and reconnect. It works every time, at least for me."