Profile: Pacer Digital Systems, Inc. designs and manufactures electronic control systems for cryogenics & refrigeration. The Cryo-Sentry monitors LN2 levels in cryogenic dewars. It has visual & audible alarms and remote alarm relay. The dewar gang alarm (DGA) is a loud audible alarm device that provides practical solution for labs with multiple storage units. The alarm initiates by the closure of any alarm relay using 2 wires.