netty/netty — pull request #956 by jeje (2013-01-18 16:24:45+00:00)
Title: RXTX: provide a wait option after opening the serial port

I'm not sure why this pause might be needed for some devices, but this is at least something which works with the devices I had trouble with.
One of the "known" device is an Arduino on Mac OS X (Lion). Perhaps the virtual serial device is too slow compared to "native" ones.