Since the cover was fastened on, I could only get photos by sticking my camera under the louvre. It was a sunny day, so I couldn't see my screen well enough to retake the photos, but I was still very surprised when I did view them. It appears to be an 8-port siren, but what is most interesting is the coding mechanism. It consists of a damper plug which fits over the air intake, and is raised and lowered by a geared lever mechanism operated by a small motor, the edge of which can barely be seen in the last photo. This probably explains why the siren sounded a "C" note and was never very loud: the damper was never completely opened! If it had, it would have been a much louder Bb note. Also, it explains the old cam-driven coding box on the wall in the old station, just like the fire horn encoder in Mount Shasta.
