You can use the 688 as a MIDI controller for the computer, but not vice-versa (it doesn't do chaselocking itself).
What you do is this:
Hook the MIDI out of the computer to the MIDI in on the 688, and out in the 688 to in on the computer.
Put the sync switch to MIDI on the 688.
It takes some experimenting to get this to work. Your best friend is the 688's manual, which I sincerely hope you have, as well as that for your software.
You have to tell your software to send/receive MIDI sync, or nothing else will happen. Unfortunately, I can't give specific instructions on this without knowing what software you're using.
Next step is to stripe a tape with MTC - MIDI time code, or the FSK signal. If you turn up channel 8 on the cue monitor and hit play on the computer, you should hear a warbling tone on the cue monitor. That's the FSK signal.
Once the tape is striped, you have seven tracks you can use to record on. This means you can take the 688 elsewhere, record your 7 tracks (or less, of course), bring it home, and the computer will consider the 688 a master sync device.
Some sound cards won't work well doing this, because full chaselock in the digital realm means some heavy signal processing. Pro Tools should be able to do it, though.
Using this method you can mix down stuff on the 688 and sync it with other events (MIDI tracks, wave sounds, etc.) on the computer.
If you have an 8-in, 8-out sound card you can dump an entire tape to the computer, too, but you don't need sync to do that.
Hope this helps. I've used this, in a limited fashion, with my 688 to sync up sounds from Cakewalk with existing tapes.
Feel free to email me if you want to chat about this.
Dex.
