There are two sizes, the mini cassettes are the most common and the regular sized ones are only for the older games. I think those old games were re-released on the mini size as well.
The dongles are filled with epoxy to keep people from looking at the circuit board. Once it's removed there's a bunch of TTL chips (buffers, counters, logic gates) and the odd PROM or EPROM. Some dongles have internal jumpers that were set up prior to being encased in epoxy. That's about it.
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Re: DU Update: Deco Cassette Update
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Re: DU Update: Deco Cassette Update
