Pin 3 Mode Setting. This is a digital input used to determine if the program will enter normal mode or the test mode. The line is read after power up, and the code runs the mode that is selected. High=normal mode, Low=test mode.
Pin 4 Sample Rate Selection. This is a digital input used to determine whether the sample rate should be 11025 Hz or 8000 Hz. High=, Low=. This setting only has an effect during normal operating mode, and it can be changed at any time during operation.