The Plus Deck 2C is a cassette deck that mounts in a 5.25" PC drive bay and is controlled over RS-232 serial. It was intended for archiving cassette tapes to mp3 - note that it can not write to cassettes. Here's the Amazon page for it:
https://www.amazon.com/Plusdeck-2c-PC-Cassette-Deck/dp/B000CSGIJW
It was initally released in the 2000s, and they are currently difficult to find. However, I always wanted one as a teenager and, as an adult, bought one for Too Much Money, and am currently writing modern tools for using it in a modern PC.
This project contains a Python library for interacting with the Plus Deck 2C
over serial, using asyncio.
For more documentation, refer to the ReadTheDocs site.