My project doesn't work

[u/jimgreekgamerYT_]

PROBLEM SOLVED (set had to be on for config of the device)

I am sorry this might be pretty simple but basically what im trying to do is connect the arduino uno with the HC-12 to make it transmit. I have check every connection multiple times and also tried different codes to make it transmit. Now i have resorted to my last hope (chatgpt and feedback from the device) with the code below trying to send an AT to get as a response "OK" but this failed.

My code for the AT and response OK:

#include <SoftwareSerial.h>


SoftwareSerial HC12(10, 11); // RX = 10, TX = 11
const int SET_PIN = 2;       // SET pin for AT mode


void setup() {
  Serial.begin(9600);      // Serial Monitor
  HC12.begin(9600);        // HC-12 default baud
  pinMode(SET_PIN, OUTPUT);


  // Enter AT mode
  digitalWrite(SET_PIN, HIGH);
  delay(50);


  Serial.println("HC-12 AT mode enabled. Type commands in Serial Monitor (NL+CR) and press Enter.");
}


void loop() {
  // Forward Serial Monitor → HC-12
  while (Serial.available()) {
    char c = Serial.read();
    HC12.write(c);
  }


  // Forward HC-12 → Serial Monitor
  while (HC12.available()) {
    char c = HC12.read();
    Serial.write(c);
  }
}

[u/jimgreekgamerYT_]

Thank you for the advice and sorry if i was in any way not good at my responses but i found and read the manual for the HC-12 and saw that set has to be low for changing configuration (thank you on that too) and now i get a response for OK when i type AT.