Thanks....I looked at the MIDI Implementation Chart, and I don't see anything about MMC. But it does say (under Real Time Messages) that FA (start) and FC (stop) are supported. But maybe that is for receiving only? There's no mention of sending.
But there is a whole section about using the RC-50 with other gear, including a whole section on MIDI, so who knows. I hate manuals...and this one looks especially daunting. I'm all about simplicity. Plug and play.