RM4SCC

It enables UK postcodes as well as Delivery Point Suffixes (DPSs) to be easily read by a machine at high speed.

PostNL uses a slightly modified version called KIX which stands for Klant index (Customer index); it differs from CBC in that it does not use the start and end symbols or the checksum, separates the house number and suffixes with an X, and is placed below the address.

They can be used with Royal Mail's Cleanmail system, as an alternative to OCR readable fonts, to allow businesses to easily and cheaply send large quantities of letters.

For the purpose of calculating the checksum, the top and bottom halves of each character can be assigned the values shown in the table below.

For example the symbol for 'B' has bottom half extensions of its first two bars, represented below as 1100, the sum of their weights being 4+2+0+0 = 6, modulo 6 of which is 0.