name: HT9170B function: DTMF Receiver package: DIP18,18 manufacturer: Holtek +--()--+ VP | 1 18| VDD VN | 2 17| RT/GT GS | 3 16| EST VREF | 4 15| DV INH | 5 14| D3 PWDN | 6 13| D2 X1 | 7 12| D1 X2 | 8 11| D0 VSS | 9 10| OE +------+ This pinout came from the Chipdir: http://www.chipdir.org/