<script>
Titanium.UI.getCurrentWindow().showInspector();

var
  host = 'ftp.somesite.com',
  user = 'someuser',
  pass = 'somepassword',
  socket = Titanium.Network.createTCPSocket(host, 21),
  eol = '\r\n';

socket.onRead(function (e) {
  var
    responseText = e.toString(),
    cmd;

  console.log('Response: ' + responseText);

  if (/^220/.test(responseText)) { // greeting
    cmd = 'USER ' + user;
  } else if (/^331/.test(responseText)) { // server is asking for passwd
    cmd = 'PASS ' + pass;
  }

  if (cmd) {
    console.log('Command: ' + cmd);
    this.write(cmd + eol);
  }
});

socket.connect();
</script>