name: HT9312DT function: 12-Memory Tone/Pulse Dialer package: SKDIP28,28 manufacturer: Holtek +--()--+ NC | 1 28| NC NC | 2 27| KT HDIB | 3 26| HDO C1B | 4 25| R4B C2B | 5 24| R3B C3B | 6 23| R2B C4B | 7 22| R1B C5B | 8 21| MODE X1 | 9 20| DTMF X2 |10 19| POB XMUTEB |11 18| HKSB VSS |12 17| VDD HFI |13 16| HFO DOUT |14 15| CLOCK +------+ This pinout came from the Chipdir: http://www.chipdir.org/