This is the electronic version of a rotary selector switch with 16 positions. It has two pushbuttons that determine whether the selector switches upward or downwards. The outputs 0 to 15 can be connected to additional driver circuits to enable it to switch higher current loads.
Switch S2 toggles the switch down while S1 toggles the switch up.
Electronic Circuits volume 1.0 - Circuit Nr. 32
The complete data of the electronic circuit described above can be found in the following book and is available from Amazon.com.
Click on the image to view the book.