using System;

public class Program

{

    private static void Decode(string data)

    {

        byte[] bArray = new byte[data.Length / 3];

​

        for(int i = 0; i <= data.Length - 3; i = i + 3)

            bArray[i / 3] = (byte)Int32.Parse(data.Substring(i, 3));

​

        if(bArray.Length > 0)

        {

            int k = 6;

            for(int i = 0; i < bArray.Length; i++)

            {

                bArray[i] = (byte)(bArray[i] - k);

                k = (k + 2) & 0xFF;

            }

        }

        string charstring = "";

        for(int i = 0; i < bArray.Length; i++)

            charstring += String.Format("{0}", (char)bArray[i]);

        Console.WriteLine("OPTIONS: " + charstring);

        string model = charstring.Substring(0, 7);

        Console.WriteLine("Model  : " + model);

        string serial = charstring.Substring(7, 6);

        Console.WriteLine("Serial : " + serial);

    }

    private static string Encode(string data)

    {

        string result = "";

        byte[] bArray = new byte[data.Length];

        for(int i = 0; i < data.Length; i++)

            bArray[i] = (byte)data[i];

        int k = 6;

        for(int i = 0; i < bArray.Length; i++)

        {

            bArray[i] = (byte)(bArray[i] + k);

            k = (k + 2) & 0xFF;

        }

        for(int i = 0; i < data.Length; i++)

            result += String.Format("{0:D3}", bArray[i]);

        Console.WriteLine(result);

        return result;

    }

    public static void Main()

    {

        //string opt = "122127121107109069068070070072074081082";

        //string opt = "108113128113109111071070070072074081082";

        string opt = "108113128113109111071070070072082077081077135090118147111142078159162168102109090171174180136134102183186192151150114195198204167177126207210216182187138219222228179199150231234240194212162243246252207224174255258264221234241188269272278230245236";

        Decode(opt);

        Encode("five_55200054 optEU optRF");

    }

}