The S5T0167 is a DTMF dialer for 4 bit binary data input from the microprocessor. When the tone enable input is low, the oscillator is inhibited and the device is in a low power consumption at standby mode.On the low to high transition of tone enable, data is latched into the device and selected the standard DTMF signals. The N-channel open drain output provides a MUTE output during tone generation.