Hi! I picked up a Casio PT-50 recently, it's a little thing with mini keys, looks like
something from 1985-90. This thing is surprisingly funky. You get the standard selection of tones (which are growing on me) but the drum patterns/sounds are fantastic!

What I'm wondering though is about these ram/rom pack things. This actually has 2
different sized packs, one you put in under a little door on the top surface and it says
"ROM/RAM pack" on the case. There is also one which is a bit bigger and it goes in
under the bottom. It didn't come with any cartridges, so I'm wondering what these do? I'm guessing they're no longer available from Casio.

Also for the bottom cartridge there are 2 holes in the case which looks like they are for two 6mm plugs that would plug into the cartridge, they are labelled "memory in" and
"memory out". This is really fascinating, I wonder what these do?