A common x224 header.
        /// <summary>
        /// Parse X224 Data
        /// (parser index is updated according to parsed length)
        /// </summary>
        /// <param name="data">data to be parsed</param>
        /// <param name="currentIndex">current parser index</param>
        /// <returns>X224 Data</returns>
        private X224 ParseX224Data(byte[] data, ref int currentIndex)
        {
            X224 x224Data = new X224();

            // X224: length
            x224Data.length = ParseByte(data, ref currentIndex);

            // X224: type
            x224Data.type = ParseByte(data, ref currentIndex);

            // X224: eot
            x224Data.eot = ParseByte(data, ref currentIndex);

            return x224Data;
        }