4556 Dual 1-of-4 inverting decoder/demultiplexer. +----------+ +---------------------------+ /1EN |1 +--+ 16| VCC |/EN| S1| S0|/Y0|/Y1|/Y2|/Y3| 1S0 |2 15| /2EN |---+---+---+---+---+---+---| 1S1 |3 14| 2S0 | 1 | X | X | 1 | 1 | 1 | 1 | /1Y0 |4 13| 2S1 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | /1Y1 |5 4556 12| /2Y0 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | /1Y2 |6 11| /2Y1 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | /1Y3 |7 10| /2Y2 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | GND |8 9| /2Y3 +---------------------------+ +----------+ [This information is part of the GIICM]