[Transcoding WITHOUT a valid serial number]

since @likeadoc did not keep his word in releasing the serialnumber generator, here the code i sent him (most of the sns will be valid):

 

from random import randrange


def get_digit(number, n):
    return number // 10 ** n % 10


def get_cross_sum(number):
    return sum([int(i) for i in str(number)])


def get_serial_number(model):
    """
    Generate a serial for the given model
    :param model: The model shall be between 0 and 1 for 0=DS3615 and 1=DS3617
    :return: The serial as string
    """
    model_type = ['LWN', 'ODN']
    lwn = range(1640, 1691, 10)
    odn = [1690] + range(1710, 1791, 10) + range(1810, 1891, 10)
    model_range = [lwn, odn]
    model_sn_count = 10
    bbb_range = range(000, 901, 100)

    xyz_range = model_range[model]
    xyz = xyz_range[randrange(len(xyz_range))]
    bbb = bbb_range[randrange(len(bbb_range))]
    element_at = randrange(model_sn_count)  # Every block contains 25 serialnumbers

    digit_x = get_digit(xyz, 3)
    digit_y = get_digit(xyz, 2)
    digit_z = get_digit(xyz, 1)

    aaa = (10 - digit_z + get_cross_sum(bbb)) % 10
    increment = [digit_x * 10 + digit_y] if (digit_y + digit_z) <= 10 else [digit_x * 10, digit_y]

    result = aaa
    for i in range(1, element_at):
        result = result + increment[(i + 1) % len(increment)]

    result = "%d%s%03d%03d" % (xyz, model_type[model], result, bbb)
    return result


if __name__ == '__main__':
    print "1: DS3615xs"
    print "2: DS3617xs"
    input_value = None
    while input_value is None:
        input_value = raw_input("Which model (1,2): ")
        if input_value == "1" or input_value == "2":
            break
        input_value = None

    model = int(input_value) - 1

    serial_number = get_serial_number(model)
    print "SerialNumber: " + serial_number

# Algorithm:
# SerialNumber is divided by -> XYZ ODN AAA BBB.
# ODN is the model specific code
# every XYZ/BBB block contains an unknown number of serialnumber and can be 5 or 25, but not too many

# AAA = (10 - (Z) + cross_sum(BBB)) modulo 10
# BBB = constant value between 000 - 900 in 100 steps
# next value for AAA -> previous value + Offset
#
# Offset is defined by:
# Y + Z <= 10, the offset is +XY, otherwise its alternated +(X*10), +Y