SainSmart iMatic with RJ45 Interface Node JS Snippet

imatic.js

#
# NodeJs code for controlling 
# SainSmart iMatic with RJ45 Interface
#
var net = require("net");

var client = new net.Socket();
client.connect(30000, '192.168.1.4', function() {
    console.log('connected to iMatic!');
});

var PREFIX  = '\xFD\x02\x20';
var POSTFIX = "\x5D";

function iMaticOn(relayId) {
    var relay = String.fromCharCode(relayId);
    var on    = String.fromCharCode(1);
    var cmd   = PREFIX+relay+on+POSTFIX;
    client.write(cmd, 'ascii');
}

function iMaticOff(relayId) {
    var relay = String.fromCharCode(relayId);
    var off   = String.fromCharCode(0);
    var cmd   = PREFIX+relay+off+POSTFIX;
    client.write(cmd, 'ascii');
}