def validate_ascii_domain(domain_str):
    """
    Validates ASCII domain str is compliant
    :param domain_str:
    :return: True for Compliant, False for non-compliant.
    """

    domain_chars = set('abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.')
    return set(domain_str).issubset(domain_chars)