The Impulse Generator IPG800 is the high voltage supply to the seismic borehole sources BIS-SH. The energy is stored in a large capacitor bank which discharges through a mechanical switch. The IPG800 is controlled by a Remote Control Unit (RCU). The RCU allows the user to start the seismic survey by a single or continuous shot release. The repetition rate is freely selectable under continuous operation. The RCU is connected to the seismograph to send an accurate trigger signal.