name: HT93215AT function: 1-Memory Tone/Pulse Dialer package: DIP18,18 manufacturer: Holtek +--()--+ HKSB | 1 18| R4B MODE | 2 17| R3B X1 | 3 16| R2B X2 | 4 15| R1B VSS | 5 14| C3B VDD | 6 13| C2B DTMF | 7 12| C1B XMUTEB | 8 11| POB MODEOB | 9 10| KTB +------+ This pinout came from the Chipdir: http://www.chipdir.org/