Communication with a payment terminal in java (serial port)

Question

I want communicate with a payment terminal in using jssc API. I send a ENQ request but I have no respond. What is wrong in my code ?

Thank you

You can find my code below :

public class CommunicationTPE {

    private int montant;
    private int caisse = 1 ;
    private int type = 0;

    private static String port; 

    private static int bauRate = 9600;
    private static int dataBits = 7;
    private static int stopBits = 1;
    private static int parity = 0;
    private int current;

    private String ENQ = "5",
                   ACK = "6",
                   NAK = "15",
                   STX = "2",
                   ETX = "3",
                   EOT = "4";

    public static CommunicationTPE comm;
    private SerialPort serialPort;

    public static void initInstance(String port) {
        comm = new CommunicationTPE();
        comm.openCommunication(port);
    }   

    public void openCommunication(String port) {
        CommunicationTPE.port = port;

        //serialPort.writeBytes(SerialPort.);//Write data to port
        if (serialPort != null && serialPort.isOpened()) {
            try {
                serialPort.closePort();
            } catch (SerialPortException ex) {
                Logger.getLogger(CommunicationTPE.class.getName()).log(Level.SEVERE, null, ex);
            }
        }

        serialPort = new SerialPort(port.trim()); 
        try {
            serialPort.openPort();//Open port
            if (!serialPort.isOpened()) {
                JOptionPane.showMessageDialog(null,"Terminal non détecté");
                return;
            }
            // bauRate : data transfer rate, dataBits : number of data bits, stopBits : number of stop bits, parity : parity
            serialPort.setParams(bauRate, dataBits, stopBits, parity);//Set params

            int mask = SerialPort.MASK_RXCHAR + SerialPort.MASK_CTS + SerialPort.MASK_DSR + SerialPort.MASK_ERR + SerialPort.MASK_BREAK + SerialPort.MASK_RING + SerialPort.MASK_RLSD + SerialPort.MASK_RXFLAG + SerialPort.MASK_TXEMPTY;//Prepare mask
            serialPort.setEventsMask(mask);//Set mask
            serialPort.addEventListener(new SerialPortReader());//Add SerialPortEventListener
        } catch (SerialPortException ex) {
            Logger.getLogger(CommunicationTPE.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public void stopCommunication() {
        try {
            serialPort.closePort();
        } catch (SerialPortException ex) {
            System.out.println(ex);
        }
    }

    public static CommunicationTPE getComm() {
        return comm;
    }


    public void initData(float montant) {
        this.montant = Math.round(montant * 100);
    }

    public void sendData() {
        try {
            if (serialPort == null || !serialPort.isOpened()) {
               openCommunication(Session.PORT_COM);
            }

            if (serialPort.isOpened()) {
                current = 0;
                boolean result = serialPort.writeBytes(ENQ.getBytes());//Write data to port
                if (!result) {
                    JOptionPane.showMessageDialog(null,"Envoie de données incomplet");
                }
            } else {
                JOptionPane.showMessageDialog(null,"Terminal non détecté");
            }
        } catch (SerialPortException ex) {
            System.out.println(ex);
        }
    }

    private String sendCommandProtocolE() {
        StringBuilder command = new StringBuilder();

        // Numéro de caisse
        String caisse = this.caisse + "";
        while (caisse.length() < 2) caisse = "0" + caisse;
        command.append(caisse);

        String montant = this.montant + "";
        while (montant.length() < 8) montant = "0" + montant;
        command.append(montant);

        // Mode de transaction, 1 = carte bancaire
        command.append("1");

        // Type de transaction, 0 = achat, 1 = remboursement, 2 = annulation, 4 = pré-autorisation
        command.append(type);

        // Code numérique pour la devise
        command.append("978");

        // Données privées
        String data = "";
        while (data.length() < 10) data = " " + data;
        command.append(data);

        return command.toString();
    }

    public class SerialPortReader implements SerialPortEventListener {

        public void serialEvent(SerialPortEvent event) {
            try {
                //byte buffer[] = serialPort.readBytes(10);
                //String value = new String(buffer, "ASCII");
                String value = serialPort.readString();

                if (value != null) {
                    if (value.trim().equals(ACK) && current == 0) {
                        serialPort.writeBytes(sendCommandProtocolE().getBytes());//Write data to port
                        current ++ ;
                    } else if (value.trim().equals(ACK) && current == 1) {
                        serialPort.writeBytes(EOT.getBytes());//Write data to port
                    }
                } else {

                }
            } catch (SerialPortException ex) {
                Logger.getLogger(CommunicationTPE.class.getName()).log(Level.SEVERE, null, ex);
 //           } catch (UnsupportedEncodingException ex) {
 //               Logger.getLogger(CommunicationTPE.class.getName()).log(Level.SEVERE, null, ex);
            } catch (Exception ex) {
                Logger.getLogger(CommunicationTPE.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }

}

score 0 · Answer 1 · answered Jul 28 '15 at 16:42

This looks similar to RS-232 for bill validators. You appear to be configuring jSSC correctly but I am suspicious of the sendData function. You are only sending the ENQ message which I don't think would actually generate a response from the slave device. You should send an entire packet to get a response, a NAK message at the very least.

See how we handle the RS-232 transaction with jSSC here: https://github.com/PyramidTechnologies/jPyramid-RS-232

score 0 · Answer 2 · answered Mar 03 '16 at 13:57

The ENQ message would receive an ACK response if the character being sent was an actual ENQ character. That is not the case in the given example. In the given example a character '5' is being sent (hex value 0x35) whereas an ENQ character has the hex value 0x05. something like "serialPort.writeByte(0x05);" would work.

Communication with a payment terminal in java (serial port)

2 Answers2