The GBM baseline triggering scheme is similar to BATSE. Two detectors are required to be above a threshold specified in standard deviations above background in the 50-300 keV energy range on a 1.024 second time-scale (although other time-scales and energy ranges are used). Rather than process the signals at each detector, the centrally located Data Processing Unit (DPU) collects, processes, and packages data from all the individual detectors. The main functions of the DPU are to digitize the analog pulse height signals, accumulate time-resolved pulse height spectra with variable time resolution, tag the spectra with time and detector information, package the data for telemetry, and use the data to realize a burst trigger and compute burst locations. The DPU also controls the operation of the instrument, including power supply settings, and accumulates housekeeping and instrument status data for inclusion in the telemetry. It acts as the sole electrical interface between the GBM and the GLAST spacecraft computer. Burst alerts and onboard burst locations provide the possibility of relocating the GLAST spacecraft to position the burst in the field-of-view of the LAT.