* [[https://mcmackins.org/stories/dos-slip.html|Connect DOS laptop to the Internet by becoming own SLIP ISP]]
  * [[https://github.com/martin-ger/esp_slip_router|Slip to wifi router using esp8266 microcontroller]]
  * [[https://github.com/ssshake/vintage-computer-wifi-modem|Heyes type of modem]]
//The Serial WIFI Modem Emulator is a RS232 DB9 connection which provides a bridge to the internet over WIFI. This device does not show up like a wifi network card on the old device. Rather it shows up as a Hayes compatible dial up modem. Instead of dialing phone numbers to connect to remote computers, it connects to remote computers via telnet.//
  * [[https://github.com/bozimmerman/Zimodem|ESP8266/ESP32/Arduino custom modem<->internet simulator with lots of features]]
  * [[https://mygpslostitself.blogspot.com/2017/07/raspberry-pi-zero-w-serial-modem.html|Raspberry pi zero w serial modem prototype]]
  * [[http://podsix.org/articles/pimodem/|The PiModem Project]]