Hello everybody 
I am new here and I don't have almost any experience with Arduino. I have Arduino Starter Kit.
I tried to connect Arduino to my old Nokia 3410 phone via FBUS. I soldered some wires to the corresponding pads on Nokia and used breadboard to play with Nokia a little bit.
I used this link: How to use Nokia F-bus to send an SMS message « insideGadgets as a reference, but I didn't have 330 Ohm resistors. Instead, I used 220 Ohm and 560 Ohm resistors in parallel. I measured voltage at both TX and RX pins, and it is 3.45 at Nokia's RX pin and 3.27 at Nokia's TX pin.
I connected the circuit like in the attached picture.
What is a good thing is that I can send and receive some kind of data. I send 128 times 'U' (0x55 in HEX), and after that I send 0x1E 0x00 0x0C 0xD1 0x00 0x07 0x00 0x01 0x00 0x03 0x00 0x01 0x60 0x00 0x72 0xD5, expecting to get back HW/SW version. Instead of that, I get the following data (it is REALLY very much different than what I expected):
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
The code I'm using is this (it is slightly adapted from the referenced link) :
#include <SoftwareSerial.h>
SoftwareSerial mySerial(10, 11); // RX, TX
byte msg[] = {
0x1E, 0x00, 0x0C, 0xD1, 0x00, 0x07, 0x00, 0x01, 0x00, 0x03, 0x00, 0x01, 0x60, 0x00, 0x72, 0xD5 };
void setup() {
 Serial.begin(115200);
 mySerial.begin(115200);
 delay(1000);
}
void loop() {
 // Initialise the F-bus
 for (int z = 0; z < 128; z++) {
  mySerial.write(0x55);
 }
 mySerial.println("");
 delay(100);
 // Send our command
 for (int x = 0; x < (sizeof(msg) / sizeof(byte)); x++) {
  mySerial.write(msg[x]);
 }
 mySerial.println("");
 // Wait for a reply
 while (1) {
  while (mySerial.available() > 0) {
   int incomingByte = mySerial.read();
   Serial.print(incomingByte, HEX);
   Serial.print(" ");
  }
 }
 Serial.println();
}
Sorry for so long post. I hope that some of you people out there can help me with debugging.
Thank you very much!
