# File lib/rqrcode/qrcode/qr_bit_buffer.rb, line 65
    def alphanumeric_encoding_start(length)
      
      put( QRMODE[:mode_alpha_numk], 4 )
      put(length, QRUtil.get_length_in_bits(QRMODE[:mode_alpha_numk], @version))
      
    end