The project consists of 2 main parts:

Hardware:

Minitel ESP32 board by iodeo
https://hackaday.io/project/180473-minitel-esp32

https://www.tindie.com/products/iodeo/minitel-esp32-dev-board/?utm_source=hackadayio&utm_medium=link&utm_campaign=project_buynow

Good ressources are available on : 

Software:  
Minitel library by eserandour

Huge thank you!

github: https://github.com/eserandour/Minitel1B_Hard
   
Universal-Arduino-Telegram-Bot by Brian Lough
Huge thank you!

github: https://github.com/witnessmenow/Universal-Arduino-Telegram-Bot

YouTube: https://www.youtube.com/brianlough

Tindie: https://www.tindie.com/stores/brianlough/

Twitter: https://twitter.com/witnessmenow

My code is pretty dirty, but it kind of works.

You need to create a bot in Telegram (Brian explains how very clearly in his videos)

Then, get the token from Botfather

The code could be improved, but my version of Minitel is not really responsive to some "advanced" functions used in the library. Formating is kind of limited if you see what I mean...

NEW: Code is now available on github. 

https://github.com/goguelnikov/TelegramMinitelChat

Do not hesitate to propose modifications and improvements!