I've been busy working on OBEX (currently over TCP/IP, but it is transport independent). OBEX should be a valid test case for the TinyTP layer of Nitro. Nitro seems to be working best on Siemens phones and worst on Ericsson models. Testing this is pretty complicated since the means to signal an error condition (or even logging some data) from within a comm tool are quite limited. For now, the focus will be on catching potentially critical states in the protocol and not do something stupid.
Interestingly enough, Nitro seems to work my Nokia 3650 at least to some extent. It connects via a regular GSM data connection, but then the phone crashes after transferring some data. I'll have to try that with a more recent firmware for the Nokia.
I've also been able to finally try a USB/IrDA adapter under Mac OS X 10.1.5, and unfortunately, it doesn't work at all. I suspect that this is due to the adapter (an Actisys IR4000US), which isn't even supported under Linux. Other adapters might work - Apple is even selling them via their European web store.