name: HT9020B function: Call Progress Tone Decoder & ABR Controller package: DIP8,8 manufacturer: Holtek +--()--+ ENV | 1 8| VDD VREF | 2 7| ENB SIN | 3 6| X2 VSS | 4 5| X1 +------+ This pinout came from the Chipdir: http://www.chipdir.org/