This is the ICD Multi-I/O (MIO) expansion for the Atari XL or XE series 8-bit computers (800XL, upgraded 600XL and 65XE and 130XE computers with an adapter not-included in this auction), which provided advanced serial (usually for modems), parallel printer port, RAMdisk, as well as SCSI hard drive support. This is the 1 megabyte (1MB) version, the larger of those available from ICD at the time. Fairly rare and sought after vintage item for the Atari 8-bit computer line.
I tested this device on a stock Atari 800XL computer, and everything that I was able to test appears to work well. I was not able to test the hard drive connection, or serial and parallel ports. I was able to test the RAMdisk, and performed RAM tests with the MIODIAG program, which passed. However, due to the age of this device, I have to offer it as-is.
Power supply is not included, but you can use any power supply from the Atari 1050 disk drive, which most of you hard core Atari fans already have, I'm sure.
Pictures show the unit connected to the 800XL computer (not included), the serial number (#575) on the back of the PBI connector. The other pictures show the screen of the built in MIO configuration screen, and running the MIODIAG burn-in test.