Converts to an int value from both ASCII and regular hex.
       The format used appears to vary based on whether the command was to
       get an existing value (regular hex) or set a new value (ASCII hex
       mirrored back from original command).

       Regular hex: 0123456789abcdef
       ASCII hex:   0123456789:;<=>?

def from_ascii_hex(text: str) -> int:
    """Converts to an int value from both ASCII and regular hex.
       The format used appears to vary based on whether the command was to
       get an existing value (regular hex) or set a new value (ASCII hex
       mirrored back from original command).

       Regular hex: 0123456789abcdef
       ASCII hex:   0123456789:;<=>?  """
    value = 0
    for index in range(0, len(text)):
        char_ord = ord(text[index:index + 1])
        if char_ord in range(ord('0'), ord('?') + 1):
            digit = char_ord - ord('0')
        elif char_ord in range(ord('a'), ord('f') + 1):
            digit = 0xa + (char_ord - ord('a'))
        else:
            raise ValueError(
                "Response contains invalid character.")
        value = (value * 0x10) + digit
    return value