A

IMPACT LINE PRINTERS, PULSE RATE INTEGRATORS, FREQUENCY METERS, FREQUENCY DEVIATION METERS, FREQUENCY-TODIRECT-CURRENT CONVERTERS, DIGITAL FREQUENCY GENERATORS, VOLTAGE AND FREQUENCY LIMIT DETECTORS, DIGITAL COUNTERS, TRANSDUCER SIGNAL CONDITIONING EQUIPMENT, COUNTER TIMERS, DIGITAL VOLTMETERS, DIRECT CURRENT TO FREQUENCY CONVERTERS