I want the empeg to control the md changer. ... :T ...does that help?

Not going to happen easily. CD/MD changers have proprietary control interfaces. Each one is different, and they all require pretty specialized circuitry. To do what you're talking about doing, you would have to:

1) Reverse-engineer the minidisc changer's interface.
2) Create a circuit that would convert serial-port commands into the proprietary signals for the changer.
3) Write a piece of software to run on the Empeg that would do the controlling for you.

As MorrisDL said, you're better off just getting a remote control interface for the MD changer and controlling it from there. But that's not cheap. Assuming your MD changer is a Sony, the RM-X69RF remote control interface MorrisDL mentioned is 129.95 at Crutchfield.

But now here comes the real question:

You have an empeg! What do you need a minidisc changer for?!?!?!

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Tony Fabris