How to develop softphone using ASP.Net?

try  
{  
    softPhone = SoftPhoneFactory.CreateSoftPhone(SoftPhoneFactory.GetLocalIP(), 5700, 5750);
	softPhone.IncomingCall += softPhone_IncomingCall;
    phoneLine = softPhone.CreatePhoneLine(new SIPAccount(true, "oz875", "oz875", "oz875", "oz875", "192.168.115.103", 5060));
    phoneLine.RegistrationStateChanged += phoneLine_PhoneLineInformation;

	softPhone.RegisterPhoneLine(phoneLine);
}  
catch (Exception ex)  
{	 
	ErrorIndicator = String.Format("You didn't give your local IP adress, so the program won't run properly.\n {0}",ex.Message);  
}

phoneLine = softPhone.CreatePhoneLine(new SIPAccount(True, "oz891", "oz891", "oz891", "oz891", "192.168.91.212", 5060));

		private static ISoftPhone softPhone;  
		private static IPhoneLine phoneLine;  
		private static PhoneLineInformation phoneLineInformation;  
		private static IPhoneCall calloperator;  
		private static IPhoneCall callcustumer;  
		private static PhoneCallAudioSender operatorSender = new PhoneCallAudioSender();  
		private static PhoneCallAudioReceiver operatorReceiver = new PhoneCallAudioReceiver();  
		private static PhoneCallAudioSender customerSender = new PhoneCallAudioSender();  
		private static PhoneCallAudioReceiver customerReceiver = new PhoneCallAudioReceiver();  
		private static MediaConnector mediaConnector = new MediaConnector();  
		public string operatorNumber,customerNumber;  
		public String ErrorIndicator;  
		

		private void InitializeSoftPhone()
        {
            try
            {
                softPhone = SoftPhoneFactory.CreateSoftPhone(SoftPhoneFactory.GetLocalIP(), 5700, 5750);
                softPhone.IncomingCall += softPhone_IncomingCall;
                phoneLine = softPhone.CreatePhoneLine(new SIPAccount(true, "oz875", "oz875", "oz875", "oz875", "192.168.115.103", 5060));
                phoneLine.RegistrationStateChanged += phoneLine_PhoneLineInformation;

                softPhone.RegisterPhoneLine(phoneLine);

                mediaConnector.Connect(operatorReceiver, customerSender);
                mediaConnector.Connect(customerReceiver, operatorSender);
            }
            catch (Exception ex)
            {
                //MessageBox.Show(String.Format("You didn't give your local IP adress, so the program won't run properly.\n {0}", ex.Message), string.Empty, MessageBoxButtons.OK,
                //MessageBoxIcon.Error);
            }
        }
		

• Handling outgoing calls: the application dials the phone numbers which were given on the interface by pressing the Submit button through the "global.BeginCall(OperatorCall)" method call.

  		public void BeginCall(bool IsCustomerCall)  
  		{  
  		    if (IsCustomerCall)  
  		    {  
  		        if (phoneLineState != RegState.RegistrationSucceeded && phoneLineState != RegState.NoRegNeeded)  
  		        {  
  		            return;  
  		        }  
  		  
  		        callcustumer = softPhone.CreateCallObject(phoneLine,customerNumber);  
  		        WireUpCallEvents(callcustumer);  
  		        customerReceiver.AttachToCall(callcustumer);  
  		        customerSender.AttachToCall(callcustumer);  
  		        callcustumer.Start();  
  		    }  
  		    else  
  		    {  
  		  
  		        if (phoneLineState != RegState.RegistrationSucceeded && phoneLineState != RegState.NoRegNeeded)  
  		        {  
  		            return;  
  		        }  
  		        calloperator = softPhone.CreateCallObject(phoneLine, operatorNumber);  
  		        WireUpCallEvents(calloperator);  
  		        operatorSender.AttachToCall(calloperator);  
  		        operatorReceiver.AttachToCall(calloperator);  
  		        calloperator.Start();
  		    }  
  		}  
  		

  This method does the call forwarding towards the operator and the customer and its parameter determines to which direction it needs to go. Before establishing a call you need to subscribe to some events for the call to be effective. The software makes these subscribes through the "WireUpCallEvents" call policy.

  		private void WireUpCallEvents(IPhoneCall call)
          {
              call.CallStateChanged += (call_CallStateChanged);
              call.DtmfReceived += (call_DtmfReceived);
          }
  		

  The "CallStateChanged" event lines out the changes that happen in the status of the call.
  
  The sound data which comes from the distant telephone arrives through the "MediaDataReceived" event.
  
  To wire up for these necessary events you only need to really start a call. You can do it with the Start() function of the "call" object.
• Rejecting incoming calls: the Ozeki VoIP SDK publishes the incoming calls through the "ISoftphone" InComingCall event for us. According to the character of the sample program the incoming calls are not interpreted so the they are immediately rejected.

  		private void softPhone_IncomingCall(object sender, VoIPEventArgs<IPhoneCall> e)  
  		{  
  		    e.Item.Reject();  
  		}  
  		

• Closing conversations: when one of the parties aborts or ends the current call then the program closes the call of the other party. This happens with the "HangUP()" method call on the IPhoneCall object of the specific party.
• Displaying the status of calls: the VoIP SIP SDK publishes the status changes that happen during the telephone call through the IphoneCall CallStateChanged event. This program handles three status in the case of "Incall" status as it also can be seen from the source code. If a change happened in the call object of the operator then it sends the call towards the customer. If one of the calls ended then it ends the other call as well with the HangupCall((IPhoneCall)sender) method. It ends the desirable call through the "IPhoneCall" object's Stop() method.