@staticmethod
def calc_crc16(buf):
    """ Drop in pure python replacement for ekmcrc.c extension.

        Args:
            buf (bytes): String or byte array (implicit Python 2.7 cast)

        Returns:
            str: 16 bit CRC per EKM Omnimeters formatted as hex string.
        """
    crc_table = [0, 49345, 49537, 320, 49921, 960, 640, 49729, 50689, 1728,
        1920, 51009, 1280, 50625, 50305, 1088, 52225, 3264, 3456, 52545, 
        3840, 53185, 52865, 3648, 2560, 51905, 52097, 2880, 51457, 2496, 
        2176, 51265, 55297, 6336, 6528, 55617, 6912, 56257, 55937, 6720, 
        7680, 57025, 57217, 8000, 56577, 7616, 7296, 56385, 5120, 54465, 
        54657, 5440, 55041, 6080, 5760, 54849, 53761, 4800, 4992, 54081, 
        4352, 53697, 53377, 4160, 61441, 12480, 12672, 61761, 13056, 62401,
        62081, 12864, 13824, 63169, 63361, 14144, 62721, 13760, 13440, 
        62529, 15360, 64705, 64897, 15680, 65281, 16320, 16000, 65089, 
        64001, 15040, 15232, 64321, 14592, 63937, 63617, 14400, 10240, 
        59585, 59777, 10560, 60161, 11200, 10880, 59969, 60929, 11968, 
        12160, 61249, 11520, 60865, 60545, 11328, 58369, 9408, 9600, 58689,
        9984, 59329, 59009, 9792, 8704, 58049, 58241, 9024, 57601, 8640, 
        8320, 57409, 40961, 24768, 24960, 41281, 25344, 41921, 41601, 25152,
        26112, 42689, 42881, 26432, 42241, 26048, 25728, 42049, 27648, 
        44225, 44417, 27968, 44801, 28608, 28288, 44609, 43521, 27328, 
        27520, 43841, 26880, 43457, 43137, 26688, 30720, 47297, 47489, 
        31040, 47873, 31680, 31360, 47681, 48641, 32448, 32640, 48961, 
        32000, 48577, 48257, 31808, 46081, 29888, 30080, 46401, 30464, 
        47041, 46721, 30272, 29184, 45761, 45953, 29504, 45313, 29120, 
        28800, 45121, 20480, 37057, 37249, 20800, 37633, 21440, 21120, 
        37441, 38401, 22208, 22400, 38721, 21760, 38337, 38017, 21568, 
        39937, 23744, 23936, 40257, 24320, 40897, 40577, 24128, 23040, 
        39617, 39809, 23360, 39169, 22976, 22656, 38977, 34817, 18624, 
        18816, 35137, 19200, 35777, 35457, 19008, 19968, 36545, 36737, 
        20288, 36097, 19904, 19584, 35905, 17408, 33985, 34177, 17728, 
        34561, 18368, 18048, 34369, 33281, 17088, 17280, 33601, 16640, 
        33217, 32897, 16448]
    crc = 65535
    for c in buf:
        index = (crc ^ ord(c)) & 255
        crct = crc_table[index]
        crc = crc >> 8 ^ crct
    crc = crc << 8 | crc >> 8
    crc &= 32639
    return '%04x' % crc
