Yes, the JUNO-D6/D7/D8 can be used as a MIDI keyboard. By connecting the JUNO-D to a computer with a data-transfer-capable USB cable, you can record MIDI data from the JUNO-D to your DAW software or use DAW software to play back MIDI data, triggering the sound generator of the JUNO-D. Additionally, with JUNO-D System Program version 1.11, the DAW CTRL function has been added, enabling enhanced control of DAW software.
The latest system program and USB driver can be downloaded from the Roland website: https://www.roland.com/global/products/juno-d6/downloads/
For detailed instructions, please refer to the "Using the DAW software" section in the JUNO-D6/D7/D8 Reference Manual and the "JUNO-D6/D7/D8 MIDI Implementation" documentation: https://www.roland.com/global/products/juno-d6/support/
Note: Use a USB cable that supports data transfer when connecting to a computer or mobile device, as charging-only cables cannot transmit data.