Node-red EnOcean in Node

nr_node_enocean_in.js

// v0.1 added else for testing
// expects binary lines like 55000A0701EBA500005B080088E4C20001FFFFFFFF4F0034
if (msg.payload.length > 20) {
    var m = msg.payload;
    console.log("ping",m.length,m.toString('hex'));
    if (m.charCodeAt(0) == 85) {
        var l = m.charCodeAt(2) + m.charCodeAt(1)*256;
        console.log("Len =",l);
        var type = m.charCodeAt(4);
        console.log("Type=",type);
        var tel = m.charCodeAt(6); // would be better as hex
        console.log("Tel =",tel);
        var rssi = m.charCodeAt(l+11);
        var i = m.substr(l+1,4);
        var id = "";
        for (a = 0; a < i.length; a++) {
       		id += i.charCodeAt(a).toString(16);
        }
        console.log("ID  =",id);
        if (tel == "165") { // It's a temp sensor (0xA5)
            var t = m.charCodeAt(9);
            msg.payload = parseInt(400 - (t*400/256))/10;
        }
        else { // It's a switch (only other option for now)
            msg.payload = m.charCodeAt(7);
        }
        msg.type = type;
        msg.tel = tel;
        msg.topic = id;
        console.log(msg);
        return msg
    }
} else {
	msg.payload = "telegram not reconised";
    msg.topic = "enon debug"; 
    return msg;
}