In a previous paper , B. Dimsdale and I reported on the use of programmed Hamming codes for error correction on a 7090. The paper generated much interest, but several readers remarked that they could not use the technique on their decimal machines since they could not manipulate the bit structure of the characters. This paper presents a modification of Hamming's technique to adapt it to such machines. It generalizes to any number base for which addition is built into the machine, and so could be used for alphabetic error correction on a machine where such operations as (A + B, literally) or (R+2, literally) or (H + S, literally) are unequivocally defined. The technique will be described for single strings of characters, but may be generalized to parallel techniques if parallel, no-carry addition is available on the machine in question. © 1961 ACM. All rights reserved.