16 E0 15 I0c 14 I1c 13 Zc 12 I0d 11 I1d 10 Zd 9 J SUFFIX CERAMIC CASE 620-09 16 1 16 1 N SUFFIX PLASTIC CASE 648-08 SN54/74LS257B VCC = PIN 16 GND = PIN 8 16 1 D SUFFIX SOIC CASE 751B-03 1 S VCC 16 2 I0a E0 15 3 I1a I0c 14 4 Za I1c 13 5 I0b Zc 12 6 I1b I0d 11 7 Zb I1d 10 8 GND Zd 9 .