def max_bitrate_ext(val):
    """
    Given ESM value, return extended maximum bit rate (Kbps).
    Please refer to 10.5.6.5, TS24.008 for more details.

    :param val: the value encoded in the ESM NAS message
    """
    if val <= 74:
        return 8600 + val * 100
    elif val <= 186:
        return 16000 + (val - 74) * 1000
    elif val <= 250:
        return 128000 + (val - 186) * 2000
    else:
        return None