It was just a periscope, and "fake" (non-lod) missiles, simulating SS-N-4s. They used radar homing, and the trick to get them to launch was to position a radar-equipped "threat", such as a destroyer, nearby. The sub would then attempt to engage the destroyer, but the missile's rapid acceleration and huge turn radius would prevent them from hitting that target. They would instead home-in on strategically-based ASRs (usually placed within a city or port facility), usually 200-400 KM from the launch point.
I made a video of such a launch, following the missile through its flight, right on down to the detonation of its simulated 1 mega-ton warhead, over a port facility on the desert map. The site that the video was hosted on is long-gone. I'd say this was around 2005-2006.