The Digital Multistation Borehole Acquisition System (MBAS-D) is a digital three-component geophone string used to receive P- and S-waves in dry or water filled boreholes. It can be used for S-wave borehole tomography or downhole surveying. Up to ten individual stations with tri-axial sensors can be connected. The system is especially designed for S-wave borehole tomography. S-wave tomography links high-resolution borehole geophysics to soil dynamic properties. S-waves need to be generated with different polarization in order to be easily recognized during data processing. Due to its shorter wavelength compared to P-waves the S-wave provides a much higher resolution.