> For the complete documentation index, see [llms.txt](https://byrzhm.gitbook.io/build-a-risc-v-chip-from-scratch/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://byrzhm.gitbook.io/build-a-risc-v-chip-from-scratch/interfaces/serial-interface/echo.md).

# Echo

```sh
sudo screen /dev/ttyUSB0 115200 # usually the fastest you can go
```

{% hint style="warning" %}
Use `ls -l /dev | grep ttyUSB0` to make sure that `/dev/ttyUSB0` exists.
{% endhint %}

## References

* [Screen User's Manual: 6.6 Window Types](https://www.gnu.org/software/screen/manual/html_node/Window-Types.html#Window-Types)