name: HT9313A function: 12-Memory Tone/Pulse Dialer package: DIP18,18 manufacturer: Holtek +--()--+ C1B | 1 18| R4B C2B | 2 17| R3B C3B | 3 16| R2B C4B | 4 15| R1B C5B | 5 14| MODE X1 | 6 13| DTMF X2 | 7 12| POB XMUTEB | 8 11| HKSB VSS | 9 10| VDD +------+ This pinout came from the Chipdir: http://www.chipdir.org/