14 excites the piezo stack 32 so as to generate an electric output signal voltage however it is contemplated that the acoustic signal may excite an accelerometer 34 or an additional piezo stack 35 so as to generate an electric output signal voltage this signal is essentially an analog signal carrying digital information the analog signal is applied to a signal conditioner 48 which operates to filter condition the analog signal to be digitalized by an nd analog to digital converter 50 the a d converter 50 provides a digitalized signal which can be applied to a microcontroller 52 the microcontroller 52 is preferably adapted to demodulate the digital signal in order to recover the data provided by the sensor 42 connected to another modem or provided by the surface the type of signal processing depends on the applied modulation i e psk qpsk qam and the like the modem 26 can therefore operate to transmit acoustic data signals from the sensors in the downhole equipment 20 along the tubing 14 in this case the electrical signals from the equipment 20 are applied to the transmitter electronics 36 described above which operate to generate the acoustic signal the modem 26 can also operate to receive acoustic control signals to be applied to the downhole equipment 20 in this case the acoustic signals are demodulated by the receiver electronics 38 described above which operate to generate the electric control signal that can be applied to the equipment 20 in order to support acoustic signal transmission along the tubing 14 between the downhole location and the surface a series of repeater modems 56 a 56 b etc may be positioned.