NXtel:Introduction
From SpecNext Wiki
NXtel is a videotex TCP/IP server and client for the ZX Spectrum Next.
See here for how to start contributing NXtel content.
Documentation for contibuting to NXtel is very lacking, so please consider helping write better documentation on this wiki, after you have learned the site and editor functionality, to help the next guy in your shoes have an easier time.
For end-users, there is a FAQ, and some existing documentation already on the GitHub wiki.