PyQt4 QTcpSocket test

import sys
from PyQt4 import QtCore,QtGui,QtNetwork

class test(QtGui.QWidget):
  def __init__(self,parent=None):
    QtGui.QWidget.__init__(self,parent)
    self.layout=QtGui.QVBoxLayout(self)
    self.toSent=QtGui.QLineEdit(self)
    self.received=QtGui.QLineEdit(self)
    self.button=QtGui.QPushButton('SEND')
    self.layout.addWidget(self.toSent)
    self.layout.addWidget(self.received)
    self.layout.addWidget(self.button)

    self.soc=QtNetwork.QTcpSocket(self)

    self.button.clicked.connect(self.connecting)
    self.soc.connected.connect(self.sending)
    self.soc.bytesWritten.connect(self.reading)


    self.show()

  def connecting(self):
    self.soc.connectToHost('192.168.1.74',23000)

  def sending(self):
    payload=self.toSent.text()
    payload.append(chr(13))
    print self.soc.writeData(payload)

  def reading(self):


    a=str(self.soc.readAll())
    print 'READ:',a
    self.received.setText(a)
    self.soc.disconnectFromHost()



app=QtGui.QApplication(sys.argv)
ins=test()
sys.exit(app.exec_())