I'm sure you know, but the BCR outputs Midi .
Midi is a serial protocol at 31,250 baud, asynchronous, 1
start bit, 1 stop bit.
It will output just about any Midi message including System Exclusive (sysex)
Info for how Midi works...
You can program the BCR with its programming language, BCL, and compile and send it with my program
Or using Mark's non-programming editor at...
His editor will also read the BCL text file (I call them *.bc2) and compile and send.
You will also find Mark's BCL documentation there as well.
If you are looking for two way communication (the Arduino back to the BCR) then you need to use the simplified (in BCL .easypar) with the easiest messages being Continuous Controller (CC)
All the best
Royce