[ih] X.25

[Carsten Bormann]

On Oct 2, 2025, at 11:50, Michael Grant via Internet-history <internet-history at elists.isoc.org> wrote:
> 
> But I don't recall any way of using X.25 for IP.

RFC 877 (obsoleted almost a decade later by RFC 1356).

We had X.25 on IBM PCs (connected to Bundespost's Datex-P [1]), connected to our BSD boxes via a serial line with SLIP on it (or just X.28/X.29 on it and UUCP, of course).
(The PCs had a rudimentary speaker, and Datex-P was slow enough that you could usefully hear something from making a click for every packet.
Originally thought as a debugging aid, we left it on as it became operationally useful.
We could hear when Datex-P became degraded as the snow melted and the water crept into the cables…)

Grüße, Carsten

[1]: https://de.wikipedia.org/wiki/Datex-P