# `ECO`: Beatmania IIDX HAPPY SKY

* Compatible main PCB: [`KNM-???`](../boards.md#knm-???)
* Compatible IO: [C02 IO](../io.md#c02-io), [D01 IO](../io.md#d01-io)
* Compatible card reader: [C02 magnetic card readers](../io.md#c02-magnetic-card-readers)

## Software revisions

* `A`
* `B`
* `C`
* `D`