Garage Door Opener with Siemens TC35i Modem and Pro Mini

#include <SoftwareSerial.h>						//Including Sotware Serial lib for second serial port to connect Siemens TC35i

String tel_1 = "+11221234567";  				//Telephone number 1
String tel_2 = "+11227654321";  				//Telephone number 2

String temp;									//Define temp string

int rxpin = 9;									//Define rx and tx pin
int txpin = 8;

byte door = 10;                  				//Relay output

SoftwareSerial serial2(rxpin,txpin); 			//RX,TX 

void setup() {

  	pinMode(door, OUTPUT);    					//Set relay port to output
    digitalWrite(door, HIGH); 					//Set relay port to high (switch relay default state)

    Serial.begin(115200);       				//Initialize HW serial port for debug
    serial2.begin(57600);   					//Initialize SW serial port for communicat with modem

    Serial.println("Starting...."); 			//Program starting
  
    delay(120000);								//Waiting for modem (120sec is enough)
    serial2.println("at");  					//Send AT Command
    Serial.println("at");
    temp = serial2.readString();
    Serial.print(temp);
    delay(1000);
  
    Serial.println("at+clip=1");  				//Send AT Command to receiving caller ID
    serial2.println("at+clip=1");
    temp = serial2.readString();
    Serial.println(temp);
    delay(1000);
  
  Serial.println("Enter to loop..."); 			//Loop is stating...
  
}

void loop() {

      digitalWrite(door, HIGH);       			//Set relay outpout to high (relay normal state)

    if (serial2.available()) {          		//Wait for SW Serial communication is active
        String str = serial2.readString();    	//Read out full string from SW serial
        temp = (str.substring(18,30));      	//Parser out from only Caller ID
        Serial.println(str.substring(18,30));   //Show Caller ID (only ID, without any text. Example: RING ect..
      
      
     if (temp == tel_1)             			//Find caller id in database
     {
        Serial.println("Telephone number 1");   //Print caller id in debug port
        serial2.println("AT H");          		//Hang up the call/ring    
    dooropen();               					//Open the door
     } 
     
     if (temp == tel_2)            				//Find caller id in database
     {
        Serial.println("Telephone number 2"); 	//Print caller id in debug port
        serial2.println("AT H");        		//Hang up the call/ring  
    dooropen();               					//Open the door
     }

   
     else {
        Serial.println("Unknow number door sill locked"); //Print to debug port
        serial2.println("AT H");              	//Hang up the call/ring  
        temp = serial2.readString();            //Eliminate "OK" feedback to AT H command 
        
     }

   }

}

void dooropen()
{
  Serial.println("Opening the door");     		//Print to debug port
  digitalWrite(door, LOW);                  	//Set relay output LOW, activate the relay
  delay(1000);                        			//Wait 1 sec 
  digitalWrite(door, HIGH);                  	//Set relay output HIGH, relay normal state
}