private void Init()
        {
            WaveIn wi = new WaveIn();

            wi.WaveFormat     = ClientInformation.waveFormat;
            wi.DataAvailable += new EventHandler <WaveInEventArgs>(wi_DataAvailableCallback);
            audioCallback.Wi  = wi;

            textBlockInfo.Text = "Calling " + ConversationPartner + "...";

            if (IsGroup)
            {
                audioService.InitCommunicationGroup(ClientInformation.Username, ConversationPartner);
                audioCallback.StartRecording();
            }
            else
            {
                audioService.InitCommunication(ClientInformation.Username, ConversationPartner);
            }
        }