In Quipu, each cluster of knots is a digit.  Some data items are not numbers but what Ascher and Ascher call number labels. They are still composed of digits, but the resulting number seems to be used as a code, much as we use numbers to identify individuals, places, or things. Lacking the context for individual quipus, it is difficult to guess what any given code might mean. Other aspects of a quipu could have communicated information as well: color-coding, relative placement of cords, spacing, and the structure of cords and sub-cords.