
Battery powered devices like the PowerBook are sometimes more sensitive to 
serial port weirdness.  I had trouble with connecting my Mac Plus to an HP 95LX
handheld.  Everything else worked okay on that port, but not the HP. (it runs
on two penlite batteries).  It turned out that the plus (by accident or by 
design flaw?) was putting a 4 volt bias on the serial port that was doing 
weird things to the HP (which has only 3v dc!).  The HP worked fine when 
connected to the printer port.  

Does your PB screen get dim or anything when connected to the device?  Have you 
tried using the printer port?

Good luck. 

--jamie
