Can't get the arduino ethernet shield to connect to a server

I’m having trouble getting the W5100 arduino ethernet shield to connect to the server ims using. The server is a audio distribution system, called biamp tesiraForte. It uses telnet to communicate with third party controllers. but is has some problems connecting to the server.


here is the code

  Telnet client

  This sketch connects to a a telnet server (
  using an Arduino Wiznet Ethernet shield.  You'll need a telnet server
  to test this with.
  Processing's ChatServer example (part of the network library) works well,
  running on port 10002. It can be found as part of the examples
  in the Processing application, available at

   Ethernet shield attached to pins 10, 11, 12, 13

  created 14 Sep 2010
  modified 9 Apr 2012
  by Tom Igoe

int ok = 0;
int ctr = 0;
int buffer[15];
char c;

char Str1[15];

int pin4 = 4;
#include <SPI.h>
#include <Ethernet.h>

// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {
  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED
IPAddress ip(192, 168, 1, 55);

// Enter the IP address of the server you're connecting to:
IPAddress server(192, 168, 1, 41);

// Initialize the Ethernet client library
// with the IP address and port of the server
// that you want to connect to (port 23 is default for telnet;
// if you're using Processing's ChatServer, use port 10002):
EthernetClient client;

void setup() {
  pinMode(pin4, OUTPUT);
  digitalWrite(pin4, HIGH);
  // start the Ethernet connection:
  Ethernet.begin(mac, ip);
  // Open serial communications and wait for port to open:
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only

  // give the Ethernet shield a second to initialize:

  // if you get a connection, report back via serial:
  if (client.connect(server, 23)) {

  } else {
    // if you didn't get a connection to the server:
    Serial.println("connection failed");


void loop() {

  while (client.available()) {
    buffer[ctr] =;

  if (ctr > 14) {
    ctr = 0;

    if (buffer[0] == 255) {
      Serial.println("FF FC 18");
      Serial.println("FF FC 20");
      Serial.println("FF FC 23");
      Serial.println("FF FC 27");
      Serial.println("FF FC 24");
      Serial.println("FF FE 03");
      Serial.println("FF FC 01");
      Serial.println("FF FC 22");
      Serial.println("FF FC 1F");

      client.println("FF FC 18");
      client.println("FF FC 20");
      client.println("FF FC 23");
      client.println("FF FC 27");
      client.println("FF FC 24");
      client.println("FF FE 03");
      client.println("FF FC 01");
      client.println("FF FC 22");
      client.println("FF FC 1F");
      ok = 1;
  while (ok == 1) {
    client.println("Level1 set level 1 -10");

  // as long as there are bytes in the serial queue,
  // read them and send them out the socket if it's open:
  while (Serial.available() > 0) {
    char inChar =;
    if (client.connected()) {

  // if the server's disconnected, stop the client:
  if (!client.connected()) {
    // do nothing:
    while (true);

I'm having trouble getting the W5100 arduino ethernet shield to connect to the server ims using.

Then start by having it connect to a different server, using TCP, as the basic client example does.

  while (client.available()) {
    buffer[ctr] =;


It is NEVER a good idea to assume that there is room in the array for however much data you want to write to it.

Why is buffer's type int? You aren't sending binary data via telnet, are you?

  while (ok == 1) {
    client.println("Level1 set level 1 -10");

If ok ever contains 1, you will spam the server until hell freezes over. Why is THAT a good idea?