> For the complete documentation index, see [llms.txt](https://captic-2.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://captic-2.gitbook.io/docs/overview/hands-on/integrating-your-robot/integration-flow/digital-i-o.md).

# Digital I/O

Read digital inputs and set digital outputs on the Captic device.

On Captic devices with digital I/O, the Integration Flow can read the device's digital inputs and set its digital outputs, for example to receive a trigger from a sensor or to send a signal to your line.

| Node    | What it does                                                                                |
| ------- | ------------------------------------------------------------------------------------------- |
| Read DI | Reads a digital input. Outputs the value in `msg.payload` and the channel in `msg.channel`. |
| Set DO  | Sets a digital output on or off.                                                            |

**Channels.** Inputs are `DI0` to `DI7` and outputs `DO0` to `DO7`. Set the channel in the node, or per message with `msg.channel` (as `0`–`7` or `DO0`–`DO7` / `DI0`–`DI7`).

**Values for Set DO.** Take the value from the message (default) or set a fixed value in the node. `1`/`0`, `true`/`false` and `on`/`off` are all accepted.

{% hint style="info" %}
The physical pin-out depends on your device. Contact <support@captic.com> to confirm your device has digital I/O and to get its wiring.
{% endhint %}