>I could use this 74HC138 thingy to get lots of buttons on a few pins to! >Same thing for leds, with some extra d-latch or something, I think I will >work that out. with the 74138 you can switch on 1 of 8 LED´s surely, but selecting the input from buttons ist not that easy. It is not an bi-directional switch like a 4056. -Michael Buchstaller