Ah, flipping tapes again, just like the good old days!
I believe that the D-6 input may be a -10 DBU (consumer level), where most pro boards output at +4 DBM. You may get overload without attenuation. I am not sure about this, but be wary. In terms of connecting to a board, you will need either a RCA > mini, 1/4" > mini, or XLR (female) > mini. It depends on the board being used, and what the sound engineer has available for AUX sends. Another option would be to patch out of another taper's deck, if there will be one at the venue, which would eliminate any overload problems (unless the lead deck is getting overloaded). That would require a basic (RCA > mini), or (mini > mini) cable, depending on the deck. There are some very good threads in taperssection regarding board patching to help educate you a bit more.
Not to sales pitch for anyone, but Ed at Kindkables.com, can make any of the above cables for you, with good quality, at a reasonable price. He is an expereiced, knowledgable taper as well, he will hook you up.
Good luck.