What do the digital outs send out exactly?

One of these days I'm going to get the 8-out board for my MPC2000XL. The 8-outs I can understand, but what do the digital outs transmit? Does it transmit just the main out signal with a left and right channel? ...or does it transmit individual stereo tracks? If I were to hook the digital output to a Digi 002r, how will Pro Tools track it? Never messed with digital connection stuff...

I thought it send a mix of all outputs in a stereo output under digital form of course .