Can I have help interperting this code? char variable somehow storing big numbers I have this GSM module I got for my arduino project and I am trying to access the call feature, but the function makes no sense.

  boolean Adafruit_FONA::callPhone(char *number) {
  char sendbuff[35] = "ATD";
  strncpy(sendbuff+3, number, min(30, strlen(number)));
  uint8_t x = strlen(sendbuff);
  sendbuff[x] = ';';
  sendbuff[x+1] = 0;
  //Serial.println(sendbuff);

  return sendCheckReply(sendbuff, "OK");
  }


This is the function however how is char being used to display a phone number in the parameter?
It's passed as a char*. This can be derived from either a string literal (e.g. "212555121") or from a String via its c_str() method.