[en] A coincidence logic module and a companion contact closure relay module utilizing the NIM Standard have been developed for criticality alarming. The units provide an ALARM whenever two or more out of N detectors become activated or when certain electronic component failures occur. The number of detector inputs can be expanded in groups of six by adding modules. Serial and parallel redundancy were used to reduce the probability of system failure. A functional description of the modules and circuit descriptions are given. Setup and operation, testing, and maintenance of the modules are described