50g

I posted this in Comp.sys.hp48, but I figured I'd post it here too.

I'm kind of newbie to the 50g (and hp calculators in general, for 
that matter), but am kind of psyched about messing around with HPGCC 
as I already know C/C++ fairly well. 

Anyway, my question, which may have already been answered some time 
ago (can't find any straight answers though, so) is what are the 
limitations of the onboard communications on the 50g? I know the 
calculator can use Kermit and XMODEM, and that pretty spectacular 
things have been done so far (Usinagaz). I'm interested in using 
either the RS232 serial port or the USB port to connect to other 
devices and ultimately collect data from them or control them, i.e. a 
PLC, a USB ethernet adapter, surveying equipment, etc. I'm not at all 
interested in using IrDA. 

I read another thread saying something about the calculator being a 
USB peripheral which apparently poses some limitations that I'm not 
seeing, as I thought the 50g can both send and receive (through all 
three IrDA, USB and RS232). Anyway, thanks in advance for any 
pertinent information on this subject. 

Cheers, Jake