[Rxtx] mac serial sniffing ?

[Philippe Barthelemy]

Hello,

A bit off-topic I must confess :

I am trying to port a C ( termios-based ) application ( not to name  
it : http://daveb.net/s710 ).
The data are supposed in two batches after a request is sent by the  
mac ( a small delay separate the two )
my problem : I only get the first batch with rxtx.org

This lead me to one question :
On Mac OS X 10..4, how can I do some low-level serial sniffing, in  
oroder to see what does transit through the port ?

Thanks in advance !

--Philippe

PS : to make my question more generic, I may add : how should one do  
sniffing on Windows ? on Linux ?