The archived data consist of count rates from the sum of two hemispherical detectors covering 4 pi steradians and operating continuously. The detectors are 3 mm thick CsI scintillators coupled to photomultiplier tubes. The nominal energy range is 25-150 keV, but the below table should be consulted to find the accurate thresholds for any day of the mission. Although the prime objectives of this investigation are the study of solar and cosmic x- and gamma-ray bursts, it should be noted that the experiment is also sensitive to solar protons and electrons. The former deposit energy directly in the scintillator if they are energetic enough, while the latter may produce x- radiation locally by bremsstrahlung. Thus although the counting rates are generally stable at about 500 c/s over the long term, there are periods of weeks to a month or so when the rates increase considerably due to particles. Examples may be found in March 1991 (solar protons) and February 1992 (particles in the Jovian magnetosphere). The time resolution of the data takes on one of four values depending on the telemetry rate and instrument operating mode: 0.25, 0.5, 1, or 2 seconds.