Arduino + TTS256 + Speakjet

I have conntected a TTS256 to an Arduino RX, TX and Speaking.
The TTS256 is connected to the Speakjet.

Everytime when i power on the circuit begins the speakjet to play some seconds random tones.

I think this are values who are in the TTS256 buffer.

What can i do to change this ?

#include <SoftwareSerial.h>
#define txPin 2
#define rxPin 3
#define busyPin 4

// set the data rate for the Speakjet Shield SoftwareSerial port
SoftwareSerial speakJet =  SoftwareSerial(rxPin, txPin);

char sayThis[256]; // string (char array) that holds bytes of incoming string

// read a string from the serial and store it in an array
// this bit of code adapted from WilsonSerialIO.pde 
void readSerialString (char *strArray) {
  int i = 0;
  if(Serial.available()) {    
    //Serial.print("reading Serial String: "); //optional: for confirmation
    while (Serial.available()){            
      strArray[i] =;
      Serial.print(strArray[(i-1)]); // for confirmation
    strArray[i] = '\0'; // append a proper null to end of string
    Serial.println(); // for confirmation

void setup(){
  // initialize the serial communications with PC:
  // initialize the serial communications with the SpeakJet-TTS256
  pinMode(rxPin, INPUT);
  pinMode(txPin, OUTPUT);
  // make sure we are ready to start talking!
  delay(1000); // this delay minimizes random spoken text in TTS256 buffer
  speakJet.println("Talking term ready");
  speakJet.print(13, BYTE); // send cr
  speakJet.print(20, BYTE); // vol
  speakJet.print(127, BYTE); //  0-127 default 96
  speakJet.print(21, BYTE); // speed
  speakJet.print(75, BYTE); //  0-127 default 114
  speakJet.print(22, BYTE); // pitch
  speakJet.print(50, BYTE); //  0-255 default 88
  speakJet.print(23, BYTE); // bend
  speakJet.print(5, BYTE); //  0-15 default 5
  speakJet.println("X"); // terminate passthruon
  speakJet.println(10, BYTE); // add linefeed (\x0A)
  SJBusy(); // wait for speakjet buffer to empty
  sayThis[0] = '\0'; // clear speakjet buffer

void loop()
  // get string sent from PC
  // speak it!
  SJBusy(); // wait for speakjet buffer to empty
  sayThis[0] = '\0'; // clear speakjet buffer before getting next string

void SJBusy(){
  delay(20); // wait 12ms minimum before checking SpeakJet busy pin
    delay(250); // wait here while SpeakJet is busy (pin 4 is true)
  delay(250); // a bit more delay after busyPin goes false