The HCC4555B, HCC4556B (extended temperature range) and the HCF4555B, HCF4556B (intermediate temperature range) are monolithic integrated circuits available in 16-lead dual in-line plastic or ceramic package and plastic micropackage. The HCC/HCF4555B and HCC/HCF4556B are dual one-of-four decoders/demultiplexers. Each decoder has two select inputs (A and B), an Enable input (E), and four mutually exclusive outputs. On the HCC/HCF4555B the outputs are high on select ; on the HCC/HCF4556B the outputs are low on select. When the Enable input is high, the outputs of the HCC/HCF4555B remain low and the outputs of the HCC/HCF4556B remain high regardless of the state of the select inputs A and B. June 1989