How master can recieve msg from slave ?

[yuranikspb]

I have problem
i am create test project in proteus

Master:
` #include <ICSC.h>
const int buttonPin = 3;
const int ledPin = 4;
const int portreadyled = 5;
const int dePin = 2;
int buttonState = 0;
ICSC icsc(Serial,'A',dePin);

void setup() {
// put your setup code here, to run once:
// initialize the button pin as a input:
pinMode(buttonPin, INPUT);
// initialize the LED as an output:
pinMode(ledPin, OUTPUT);
pinMode(2,OUTPUT);
Serial.begin(9600);
icsc.begin();
icsc.registerCommand('G',&check);
delay(2000);
digitalWrite(ledPin, HIGH);
delay(100);
icsc.send('B', 'S');

}

void loop() {
icsc.process();
}
void check(unsigned char src, char command, unsigned char len, char *data)
{
digitalWrite(ledPin, LOW);

} `

Slave :
` #include <ICSC.h>
#include <String.h>
const int buttonPin = 3;
const int ledPin = 4;
const int dePin = 2;
int buttonState = 0;

ICSC icsc(Serial,'B',dePin);
void setup() {
// put your setup code here, to run once:
// initialize the button pin as a input:
pinMode(buttonPin, INPUT);
// initialize the LED as an output:
pinMode(ledPin, OUTPUT);
pinMode(2,OUTPUT);
Serial.begin(9600);
icsc.begin();
icsc.registerCommand('S',&stat);
}
void loop() {

icsc.process();

//icsc.send('A', 'G');
}
void stat(unsigned char src, char command, unsigned char len, char *data)
{

delay(1000);
for (int i=0; i <= 15; i++){
icsc.send('A', 'G');
icsc.process();
delay(50);
}

} `
Algorithm:
master send to slave command and led is high
slave recieve command wait and 15times try send to master command for led is LOW

master react only on 5
why ?