Serial-to-telnet dongles have long existed, but flavoring it with Hayes AT commands and emulating RING is adorable.I envy them their success in getting hardware flow control working.
Also it supports botnets, to which your Apple ][ might otherwise have been regrettably immune! "Over-the-air firmware updates. [...] No password protection of web server configuration."
Previously, previously, previously, previously, previously, previously, previously.
One of the nicest things about the ESP8266 family (I think that's the chip in the middle of the board) is that it's AT-programmable. I mean, you can make an outgoing TCP connection using AT commands. This is great, because it means all of my previous learning using modems translates to the modern web era.
I did almost manage to get zork running on one of them. Boy, not having virtual memory is a pain.
Please be advised: The Dactyl-ManuForm Keyboard: a fork of the Dactyl, a parameterized, split-hand, concave, columnar, ergonomic keyboard.