Prueba con esto.
// http://arduiniana.org/libraries/newsoftserial/
#include <NewSoftSerial.h>
byte query[8] = {
0xAA, 0x00, 0x03, 0x25, 0x26, 0x00, 0x00, 0xBB};
byte led1[8] = {
0xAA, 0x00, 0x03, 0x87, 0x18, 0x0a, 0x96, 0xBB};
byte led2[8] = {
0xAA, 0x00, 0x03, 0x88, 0x18, 0x0a, 0x99, 0xBB};
byte buzzer[8] = {
0xAA, 0x00, 0x03, 0x89, 0x18, 0x0a, 0x98, 0xBB};
#define rxPin 2
#define txPin 3
NewSoftSerial rfid( rxPin, txPin );
void setup()
{
Serial.begin(115200);
rfid.begin(9600);
Serial.println("setup() ends");
}
byte val;
int i ;
void loop()
{
for (i=0 ; i<8 ; i++){
rfid.print(query[i]) ;
}
delay(50);
while(rfid.available()>0){
val=rfid.read();
Serial.print(val, HEX);
Serial.print(" ");
}
Serial.println("--");
}