name:         HT680
function:     3**18 Series of Encoders
package:      DIP/SOP18,18
manufacturer: Holtek

     +--()--+
AD11 | 1  18| VDD
AD12 | 2  17| A9
AD14 | 3  16| A8
AD15 | 4  15| A7
DOUT | 5  14| A6
  TE | 6  13| A3
OSC2 | 7  12| A2
OSC1 | 8  11| A1
 VSS | 9  10| A0
     +------+


This pinout came from the Chipdir:
http://www.chipdir.org/