RIO control for french phones in Javascript

rio.js

function validate_isRIO(fullRIO, telephone) {
	// fullRIO is id+ctlKey
	var id = fullRIO.substr(0,fullRIO.length -3);
	var ctlKey = fullRIO.substr(fullRIO.length -3, 3);
	var ordre = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789+";
	var a = b = c = 0;

	var concat =  id + telephone;
	console.log(concat);

	for (var i = 0; i < 19; i++) {
		var position = ordre.indexOf(concat[i]);
		a = (1 * a + position) % 37 ;
		b = (2 * b + position) % 37 ;
		c = (4 * c + position) % 37 ;
	};
	var ccc = ""+ordre[a] + ordre[b] + ordre[c];
	if (ctlKey !== ccc) {
		console.log(ccc,ctlKey);
		return false;
	} else {
		var r = new RegExp("^[0-9]{2}[EP]{1}[A-Za-z0-9]{6}"+ctlKey+"$");
		console.log(r)
		return (id +ctlKey).match(r) !== null;
	}
}