Here’s a 2015 post showing how someone hooked up an ESP board to an adapter for around $20 buying from US sellers. http://atariage.com/forums/topic/244959-using-esp8266-wifi-microcontroller-as-serial-internet-modem/ Roger Taylor has been Telnetting from his virtual CoCo the past week or so using his ANSI terminal program as well as Ultimatetm.