Inconsistent prob when adding listeners to serial ports for sending AT cmds

Question

I have an app that sends and receives SMSs from two different cell phone carriers (lets say verizon and sprint by example).
For that matter i have two cell phones, exactly the same model, one from each carrier, connected to the PC serial ports, COM, COM6 and COM7 being aware that they are available.
-The application communicats with the phones through the a serial communication API and sending AT commands.
-The application can send messages correctly from both phones within the same transaction, this is, i click in send message and the message is sent from both phones.
The problem is when receiving, getting the SMS received by the phones:
-When i have ONE phone connected to the PC it work properly for both phones.
-When i have BOTH phones connected, only Carrier1 phone receives properly.
When checking, i just find out that the problem rises when i try to add the listeners (see code comments below).
When both phones connected there seems to be a problem that i cant figure out, and may be its a conceptual misunderstanding from me.
I attach the code if you can help me,
thank you,
fernando
// class fields
private static String PORT_CARRIER1;
private static String PORT_CARRIER2;
private static CommPortIdentifier portId;
private static Enumeration portsList;
private static SerialPort carrier1SP;
private static SerialPort carrier2SP;
private static InputStream carrier1_input;
private static InputStream carrier2_input;
private static OutputStream carrier1_output;
private static OutputStream carrier2_output;
// ... all the code below is from the app method where everything is initializated     
portsList = CommPortIdentifier.getPortIdentifiers();
while(portsList.hasMoreElements()){
     portId = (CommPortIdentifier) portsList.nextElement();
     if(portId.getPortType() == CommPortIdentifier.PORT_SERIAL){          
          // try to open ports
          try{
               if(portId.getName().equals(PORT_CARRIER1))
                    carrier1SP = (SerialPort) portId.open("SMS", 5000);
               else if(portId.getName().equals(PORT_CARRIER2))
                    carrier2SP = (SerialPort) portId.open("SMS", 5000);
               else System.out.println("Error " + portId.getName());
          }catch(PortInUseException piue){
               System.out.println("Exception while opening serial ports: "+piue.getMessage());
               continue;
          // try to open input streams
          try{
               if(portId.getName().equals(PORT_CARRIER1))
                    carrier1_input = carrier1SP.getInputStream();
               else if(portId.getName().equals(PORT_CARRIER2))
                    carrier2_input = carrier2SP.getInputStream();
          }catch(IOException ioe){
               System.out.println("Exception while opening input streams: "+ioe.getMessage());
               continue;
          // try to open output streams
          try{
               if(portId.getName().equals(PORT_CARRIER1))
                    carrier1_output = carrier1SP.getOutputStream();
               else if(portId.getName().equals(PORT_CARRIER2))
                    carrier2_output = carrier2SP.getOutputStream();
          }catch(IOException ioe){
               System.out.println("Exception while opening output streams: "+ioe.getMessage());
               continue;
          // adding listeners
          try{
               if(portId.getName().equals(PORT_CARRIER1))
                    carrier1SP.addEventListener(new ListenerPuerto(this, carrier1_input, "CARRIER1"));
               else if(portId.getName().equals(PORT_CARRIER2))
                    carrier2SP.addEventListener(new ListenerPuerto(this, carrier2_input, "CARRIER2"));
          }catch(TooManyListenersException tmle){
               System.out.println("Error while adding listeners: " + tmle.getMessage());
               continue;
          // Adding specific event to listeners
          if(portId.getName().equals(PORT_CARRIER1))
               carrier1SP.notifyOnDataAvailable(true);
          else if(portId.getName().equals(PORT_CARRIER2))
               carrier2SP.notifyOnDataAvailable(true);
          // Setting params to serial communication
          try{
               if(portId.getName().equals(PORT_CARRIER1)){
                    carrier1SP.setSerialPortParams(9600, SerialPort.DATABITS_8, SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);
                    carrier1 = true;
               }else if(portId.getName().equals(PORT_CARRIER2)){
                    carrier2SP.setSerialPortParams(9600, SerialPort.DATABITS_8, SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);
                    carrier2 = true;
          }catch(UnsupportedCommOperationException uscoe){
               System.out.println("Error while setting params for serial communication: " + uscoe.getMessage());
               continue;
          // ... nothing else important ...thanks in advance

Answer 1

Thinking of a java application as its what I am most
comfortable with, but also thinking of having an
apache server, and using jsp pages or servlets...
because I hate formatting things in a java frame..
have never quite mastered that! Any thoughts on what
I should use?I'd prefer a Swing GUI for a maximum of controls. If you have any problems regarding layout, you can post concrete questions here (or even better: the Swing forum).
And my main stumbling block would be how do I send
signals to the green light from the computer? How do
I get signals from the light beams to the computer?
How do I use a serial port (for eg) from a java app.There's an additional library for serial I/O, it's named javax.comm ... should be downloadable somewhere on the java.sun.com site.