name:         HT6P12
function:     Learning Car Alarm Decoder
package:      DIP20,20
manufacturer: Holtek

             +--()--+
        LOCK | 1  20| ACC(DI)
      UNLOCK | 2  19| OPT2(DO)
SIREN(CHIRP) | 3  18| LEARNB(LED)
         ARM | 4  17| DIN
      ON/OFF | 5  16| OSC
          Q3 | 6  15| VDD
         VSS | 7  14| RESB
   CLEAR(CS) | 8  13| FLASH
    OPT1(SK) | 9  12| AL+
        TRIG |10  11| AL-
             +------+


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