I have picked up a 7618 Alpine HU- circa 1991. I want to go with some old school stuff like I had back in the day for my 91 Z28. I will use this HU and an Alpine 3321 0r 3331 EQ most likely. (wish I could find a 3318 EQ, if anybody knows what that is- you know how sweet they were). But, I want to be able to play MP3 from my smartphone too. I will probably get a changer (m-bus, like 5959 or 5952) that will work with my HU. But, have also thought about using two head units along with the 3321. I have a cda-9805, and it would support an adapter with input for my smartphone. Thinking about using the pac as21 to allow two head units. Anybody have any other ideas? Anybody know how to properly wire in the brown/white "pause" wire on this 7618? I think it could be wired to utilize another HU, but not sure how that wire works and I don't have a manual.

If anybody has any old school Alpine expertise or even equipment/adapters/cables, please let me know.