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The Roland DJ-202 is an all-in-one USB MIDI controller with a built in sound card. It has controls for 2 decks that can be toggled between decks to play with 4 decks. As a special feature it's got an in-built sequencer with 8 sounds from the TR-808 and the TR-909 drum machines (TR-606 and TR-707 are available via firmware update).
You can download the latest drivers and firmware from https://www.roland.com/global/products/dj-202/downloads/.
The DJ-202 is a USB class compliant MIDI and audio device, so it's plug-and-play on Linux.
If the device is not properly detected as a MIDI device, you need to enable generic mode in the system settings:
A mapping is currently being developed, see Github