> For the complete documentation index, see [llms.txt](https://docs.mixeffect.app/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mixeffect.app/automate/osc/messages/upstream-keyers/on-air.md).

# On Air

| Message                 | Description                                                                            | Arguments |
| ----------------------- | -------------------------------------------------------------------------------------- | --------- |
| `/mixeffect/usk/on-air` | Sets the On Air status for the selected Upstream Keyer in the selected Mix Effect Bus. | Multiple  |

| Argument | Type    | Description                                          |
| -------- | ------- | ---------------------------------------------------- |
| On Air   | Integer | <p>0 = Off<br>1 = On<br>2 = Toggle</p>               |
| USK      | Integer | One-based index of the Upstream Keyer. Default is 1. |
| M/E      | Integer | One-based index of the Mix Effect Bus. Default is 1. |