I am doing most of the debugging on a laptop, so the code pretty much "just works" when flipped over to the empeg.

But.. the empeg, courtesy of Hijack, has a very large number of things resembling serial ports for debug purposes: telnet sessions.

So I just telnet into the empeg over ethernet to run/debug there when needed. stdout/stderr/stdin are all directed to the telnet session when running code such as this. The serial port has to be opened manually: /dev/ttyS1

So you need one serial port for the BT board. And a telnet session for debugging. No need for a third one (the code is already on the empeg). Use /proc/empeg_notify for player status/state -- some enhancements required and forthcoming!

For player commands, I forget exactly how, but there is a way to inject those to the player even when "Apps use Serial Port" is enabled.