The 54HSC/T630 is a 16-bit parallel Error Detection and Correction circuit. It uses a modified Hamming code to generate a 6-bit check word from each 16-bit data word. The check word is stored with the data word during a memory write cycle. During a memory read cycle a 22-bit word is taken from memory and checked for errors. Single bit errors in data words are flagged and corrected. Single bit errors in check words are flagged but not corrected. The position of the incorrect bit is pinpointed, in both cases, by the 6-bit error syndrome code which is output during the error correction cycle.