Revision as of 08:18, 21 June 2010

Problem

How to capture the Cell Info, which is displayed on the home screen of most of the GSM phones, if you set the Cell Info Display: ON in your phone settings. Cell info provides some (area)location related text info about the cell tower our device is present at the moment, along with some service providers advertisements. We don't have direct API in Java ME to capture this Cell Info from our application.

Solution

This Cell info is broadcasted as CBS (Cell Broadcast Service) message by the cell towers and received by all the GSM phones connected to this tower on certain predefined Channel (generally 050) by most of the service providers. Thus our Java ME application can listen to this CBS Channel using Push Registry and capture this information

Sample Code

Imports

import javax.wireless.messaging.*;
import javax.microedition.io.PushRegistry;

setupListening

Register your Midlet for Listening to CBS port 50 and setup a Message Listener

public void setupListening()
{        
        try{
	    PushRegistry.registerConnection("cbs://:50",this.getClass().getName(),"*");
        }catch(Exception e){}
        String[] connList;
        connList = PushRegistry.listConnections(true);
	if((connList == null) || (connList.length == 0))
	{
	  // You can exit the app, if you want
	}
	else 
        { 
	    try{
		msgconn = (MessageConnection)Connector.open("cbs://:50");
	        msgconn.setMessageListener(this);
	    } catch( IOException e){ e.printStackTrace();}
         }
}

notifyIncomingMessage

To Retrieve the CBS message payload.

public void notifyIncomingMessage(MessageConnection conn)
{
  try{
	txtmsg =(TextMessage)msgconn.receive();
  }catch(Exception e){System.out.println(e);}
  from = txtmsg.getAddress());
  Msg = txtmsg.getPayloadText();
  // Display from & Msg			
}

Note

WMA 120/205 does not support CBS on most of the Nokia S40 devices, it works on Nokia S60 and other devices.

The support for receiving CBS messages has been introduced in newer Series 40 5th Edition, Feature Pack 1 devices, all Series 40 5th Edition, Feature Pack 1 Lite devices and all Series 40 6th Edition devices.

--Submitted by Amitabh Srivastava at 16:10(IST), 27 August 2009.