# FX.25

AI-generated

Forward error correction for [AX.25](../ax25/index.html.md):
the usual [HDLC](../hdlc/index.html.md) frame is wrapped in a Reed-Solomon code block,
preceded by a correlation tag that says which code was used.
A receiver that knows FX.25 can repair damaged bits;
one that doesn’t still finds the ordinary frame inside
and decodes it as before.

## References

* [FX.25 specification](http://www.stensat.org/Docs/Docs.htm) (Stensat Group)
* [Reed-Solomon error correction on Wikipedia](https://en.wikipedia.org/wiki/Reed%E2%80%93Solomon_error_correction)