The revision of this Recommendation is made to harmonize with new Recommendation G.766. This Recommendation is applicable to the design of digital circuit multiplication equipment intended for, but not limited to, use in an international digital circuit. Freedom is permitted in design details which are not covered in this Recommendation. This Recommendation includes channel check procedure A-Law and m-law test vectors as an electronic attachment. It includes also the SDL diagrams for the DCME example of subclause A.3 as an electronic attachment.