In the following example, the MAC address of the Slave Bluesmirf is 000666123ABC. The example also assumes that the RX and TX are connected to pins 0 and 1. Here's the code for both Master ans Slave:

btsample

//Master code
void setup() {
  Serial.begin(115200);
  Serial.print("$$$");
  delay(100);
  Serial.println("SM,1");  delay(100);
  Serial.println("C,000666123ABC");
  delay(100);
  Serial.println("---");
}


//Slave code
void setup() {
  Serial.begin(115200);
  Serial.print("$$$");
  delay(100);
  Serial.println("SM,0");
  delay(100);
  Serial.println("---");
}