> ## Documentation Index
> Fetch the complete documentation index at: https://help.ondeckapps.com/llms.txt
> Use this file to discover all available pages before exploring further.

# OSC: receive and send control messages in Relay

> Configure OSC receive and send workflows in Relay for automation and control.

Relay can receive and send OSC messages over the network.

## Enable OSC receive

1. Open `Relay > Settings`.
2. Select <Icon icon="radio" /> **External Control**.
3. Switch to `OSC`.
4. Turn on `OSC Listener`.
5. Set the listen port.
6. Point the sender at this Mac's IP and that same UDP port.

## Use OSC in Relay

* Use OSC Receive triggers in Automation View — set the address pattern you want to match (for example `/relay/trigger1`), and the trigger fires whenever a message arrives at that address.
* Use OSC Send actions to transmit a message to a target IP and port (defaults to port `9000`) at an address you define.
* Use OSC from Button modules when configured.

OSC sending and automation are improved in 1.2.2, and device discovery during onboarding is more reliable, so the Setup Wizard can find OSC-capable devices more consistently.

Beyond the main OSC listener, Relay can run additional custom listening ports at the same time — useful if you want to keep OSC traffic for different purposes (say, a console integration vs. a lighting console) isolated on separate ports rather than sharing one.

The `External Control` page also shows the current IP address, message counts, and the most recent OSC packet so you can validate traffic before wiring it into a graph.

## Troubleshooting

If packets do not arrive, confirm the sender IP target, port, Local Network permission, and that no other app is already bound to the same port.