RTI display hack

Hello,

There was few information how to hack my cars RTI display to connect other devices to it. But I'm stuck at activating the screen. And I think it's because of old scripts, which activating device screen. It sends signal trough serial data and when switching to BIN to see what data it sends it sends some of unknown data also, which it looks shouldn't be sent. So the code is:

// Connect:
// Screen PIN 4 to Arduino PIN 2 (TX)
// Screen PIN 7 to Arduino ground

enum display_mode_name {RTI_RGB, RTI_PAL, RTI_NTSC, RTI_OFF};
const char display_modes = {0x40, 0x45, 0x4C, 0x46};
const char brightness_levels = {0x20, 0x61, 0x62, 0x23, 0x64, 0x25, 0x26, 0x67, 0x68, 0x29, 0x2A, 0x2C, 0x6B, 0x6D, 0x6E, 0x2F};

//int current_display_mode = RTI_OFF;
int current_display_mode = RTI_NTSC;
bool send_brightness = true;
char current_brightness_level = 13;

//delay between bytes, ms
const int rti_delay = 100;
int once = 1;

void setup() {
Serial.begin(2400);
}

void loop() {

rtiWrite(display_modes[current_display_mode]);

if (send_brightness)
rtiWrite(brightness_levels[current_brightness_level]);
else
rtiWrite(0x40);

rtiWrite(0x83);

}

void rtiWrite(char byte) {
Serial.print(byte, BIN);
delay(rti_delay);
}

And BIN output on serial monitor shows:
01001100
01101101
11111111 - strange data
11111111 - strange data
11111111 - strange data
10000011
I believe I'm not able to activate my screen because of this interfered strange data bits as. But I can't find solution how to get rid of them. Anyone here can help me with that? Thank you in advance.