CatSynth pic: Rudy the Rack Cat

From Ivan, we have Rudy the Rack Cat:

I am curious about a couple of the items in the rack. For example, the unit labeled as a “PCA-200 Low-Frequency Synthesizer”, and it's neighor below. Anyone know anything about them? The only references I can find to “PCA200” are a measurement device and an old ATM networking device.