public string BTConvert(short i)
        {
            if (i < 0)
            {
                return (short.MaxValue + 1 - i).ToString("X2").PadLeft(6, '0');
            }
            else
            {
                return i.ToString("X2").PadLeft(6, '0');
            }
        }

        public short BTConvert(string s)
        {
            short i = short.Parse(s, System.Globalization.NumberStyles.HexNumber);
            if (i < 0)
            {
                return (short)(short.MaxValue + 1 - i);
            }
            else
            {
                return i;
            }
        }