Abstract: A miniaturized autonomous digital depth. sounder was developed for automatic storing and recording of sea bottom depth, along with communication to various marine equipment, (chart plotter, GPS) using NMEA 0183 protocol. The analog part of the sounder consists of the miniature HEXFET transmitter and the one chip double opamp receiver. The digital part constitutes the PIC microcontroller, with a built-in analog-to-digital converter (ADC) and universal asynchronous transmitter (UART). Such an. architecture allows sampling and storing the echo in compressed form in PIC's RAM memory. The UART allows transmission of the data acquired by the sounder between successive pings, via the serial line. The sounder software provides bottom tracking procedure, which can be remotely set up and reconfigured by operator. The sounder design is now under commercialization in C-MAP Group in Italy.