#include <TinyWireM.h>                  // I2C Master lib for ATTinys which use USI
#define Node_Addr   0x48              
byte x = 0x01;
int c = 0;
boolean state;

#include "SoftwareSerial.h"
const int Rx = 4; // this is physical pin 7
const int Tx = 3; // this is physical pin 6
SoftwareSerial mySerial(Rx, Tx);

void setup() {
  // put your setup code here, to run once:
  TinyWireM.begin();                    // initialize I2C lib
  pinMode(Rx, INPUT);
  pinMode(Tx, OUTPUT);
  mySerial.begin(4800); // send serial data at 9600 bits/sec
}

void loop() {
 if(mySerial.available()){
    c = mySerial.read();
    delay(100);
    if(c==97){
        TinyWireM.beginTransmission(Node_Addr);
        x = 0x01;
        TinyWireM.send(x);                 // if one-shot, start conversions now
        TinyWireM.endTransmission();          // Send 1 byte to the slave
        delay(1000);                           // if one-shot, must wait ~750 ms for conversion    
    }else if(c==98){
        TinyWireM.beginTransmission(Node_Addr);
        x = 0x00;
        TinyWireM.send(x);                 // if one-shot, start conversions now
        TinyWireM.endTransmission();          // Send 1 byte to the slave
        delay(1000);                           // if one-shot, must wait ~750 ms for conversion
    }
  }

}

#include "TinyWireS.h"                  // wrapper class for I2C slave routines
#define Node_ADDR   0x48              // 7 bit I2C Address for Node
#define LED         4              // ATtiny Pin 3
byte byteRcvd = 0x00;

void setup() {
  // put your setup code here, to run once:
  pinMode(LED,OUTPUT);
  TinyWireS.begin(Node_ADDR);
}

void loop() {
  // put your main code here, to run repeatedly:
  if (TinyWireS.available()){           // got I2C input!
    byteRcvd = TinyWireS.receive();     // get the byte from master
    if(byteRcvd == 0x01){
      digitalWrite(LED,HIGH);
    }else{
      digitalWrite(LED,LOW);
    }
  }
  delay (10);
}