This instrument is a general-purpose, digital ratemeter with a built-in scaler that provides timed counts over a user-specified period. This system will store detector setup information for up to two detectors so personnel can easily change detectors in the field. The LCD presents readings in a four-digit moving decimal format together with one of a wide range of available units of measure and is accompanied by several operational and alert icons. The LCD backlight can be activated and remains lit for a user-adjustable interval. This instrument features adjustable alert and alarm setpoints for both the Ratemeter and Scaler modes. Front-panel controls include a rotary switch for selecting between Off, Ratemeter Mode, and Scaler Mode; switches for audio on/off and fast/variable response time; and push-buttons for activating the LCD backlight and for either resetting the counts or acknowledging alarms. A locking toggle switch facilitates swapping detectors while preventing accidental switching.