Post

http://www.gweep.net/~prefect/eng/reference/protocol/midispec.html

It's actually a bit more like what we have in ham radio with packet radio...digital bursts as specific "packets" with distinct destinations, other SYSEX data, and the note on/off/# that comprises most of it. And m00dawg's quite right about the optoisolators...they do a good job of compensating for voltage changes so that most any signal still gets converted back to a digital stream on "wire". And if you do something like, say, plugging the MIDI into a synth and a power outlet (not sure HOW, but I'm sure someone's tried), it'll blow the opto to kingdom come, but everything else stays more or less safe.