https://www.lilygo.cc/products/t-call-v1-4
I want to get you guys full source code for this

client.print(String("GET ") + resource + " HTTP/1.1\r\n");
client.print(String("Host: ") + server + "\r\n");
client.print("Connection: close\r\n\r\n");
client.println();

it is basically connects to server and works with relay module. https://youtu.be/J9ziYzmiW9I?si=YjWNLOmrC5ZIr9G6 here is information for nodemcu but i am having trouble to use this system to lilygo ttgo t-call sim800H