void Session_Start(object sender, EventArgs e) 
{
....
// Задаём обработчик события изменеие состояния соединения
_PhoneClient.OnConnectionStateChange += new myConnStateHandler(OnConnectionStateChange);
....
}

// Обработка события "Изменение состояния соединения"
private void OnConnectionStateChange(......)
{
   switch (e.NewState)
   {
       case Nortel.CCT.ConnectionState.Alerting:
         Session["StateText"] = "вызов...";
         break;
   }
}

    void Session_Start(object sender, EventArgs e) 
    {
        NCCTToolkit _PhoneClient = null;
        
        string      StatusText = "";
        string      StateText = "";
        string      CLIDText = "";
//        int Loads =  0 ;
//        int Inits =  0 ;

 //       int UnLoads =  0 ;
 //       int Disposed =  0 ;

        Session.Add("StatusText", StatusText);
        Session.Add("StateText", StateText);
        Session.Add("CLIDText", CLIDText);

//       Session.Add("Inits", Inits);
//      Session.Add("Loads", Loads);
//
//      Session.Add("UnLoads", UnLoads);
//      Session.Add("Disposed", Disposed);
       
        // Code that runs when a new session is started
        string Server = ConfigurationManager.AppSettings["NCCTServerAddress"];
        string Port = ConfigurationManager.AppSettings["NCCTServerPort"];

        try
        {
            // Инициализация объекта для работы с телефонией
            _PhoneClient = new NCCTToolkit(Server, Convert.ToInt32(Port), Environment.MachineName);

            _PhoneClient.Connect();

            _PhoneClient.selTerminal.Terminal = _PhoneClient.Terminals[ 0 ];
            _PhoneClient.selAddress.Address = _PhoneClient.Terminals[ 0 ].RelatedAddresses[ 0 ];

            // Задаём обработчик события изменеие состояния соединения
            _PhoneClient.OnConnectionStateChange += new NCCTToolkit.myConnStateHandler(OnConnectionStateChange);
        }
        catch //(Exception ex)
        {
            if (_PhoneClient != null)
            {
                if (_PhoneClient.IsConnected)
                    _PhoneClient.Disconnect();

                _PhoneClient.Dispose();

                _PhoneClient = null;
            }
            
            Session.Abandon();
        }

        Session.Add("PhoneClient", _PhoneClient);
    }
    
    private void OnSessionDisconnected()
    {
    }

    // Обработка события "Изменение состояния соединения"
    private string OnConnectionStateChange(Nortel.CCT.ConnectionStateEventArgs e)
    {
        string CLID = "";

        switch (e.NewState)
        {
            case Nortel.CCT.ConnectionState.Alerting:
                HttpContext.Current.Session["StateText"] = "вызов...";

                try
                {
                    if (e.Contact != null)
                    {
                        // Определяем номер звонящего (АОН)
                        if (e.Contact.CallingAddress != null)
                            CLID = e.Contact.CallingAddress.Name;
                        else
                            CLID = "";
                    }
                    else
                    {
                        CLID = "";
                    }
                }
                catch
                {
                    CLID = "";
                }

                HttpContext.Current.Session["CLIDText"] = CLID;
                break;

            case Nortel.CCT.ConnectionState.Established:
                HttpContext.Current.Session["StateText"] = "уcтановлено";
                break;

            case Nortel.CCT.ConnectionState.Disconnected:
                HttpContext.Current.Session["StateText"] = "завершено";
                HttpContext.Current.Session["CLIDText"] = "";
                break;
        }
    }