EFTPOS - Protocol test connection V. 3.00 (revision:07) - https://en.wikipedia.org/wiki/EFTPOS - simple test to communicate with MyPAX S800 Terminal

eftpos-test.js

var net = require('net');

var HOST = '192.168.9.111';
var PORT = 20008;

const STX = 0x02; // Start transaction
const ETX = 0x03; // End transaction
const SEP = 0x1C; // Field separator

var client = new net.Socket();
client.connect(PORT, HOST, function() {
    console.log('CONNECTED TO: ' + HOST + ':' + PORT);
    let str = "POST03S00A234567890123456KSTEST06        123412340000";
    let c = Buffer.from(str);
    let msg = Buffer.concat([c, Buffer.from([ETX])]);
    let d = Buffer.concat([Buffer.from([STX]), msg]);
    let lrcByte = calculateLRC(msg);
    let payload = Buffer.concat([d, Buffer.from([lrcByte])]);
    console.log(payload.toString('hex'));
    client.write(payload);
});

// Add a 'data' event handler for the client socket
// data is what the server sent to this socket
client.on('data', function(data) {
    console.log('DATA RESPONSE: ', data.toString('hex'));
    // Close the client socket completely
    client.destroy();
});

// Add a 'close' event handler for the client socket
client.on('close', function() {
    console.log('Connection closed');
});


function calculateLRC(bytes) {
    var lrc = 0;
    for (var i = 0; i < bytes.length; i++) {
        lrc ^= bytes[i];
    }
    return lrc;
}