[ COUNTER-TIMERS, PLUG-IN FREQUENCY EXTENDERS FOR COUNTER-TIMERS, FREQUENCY METERS, PLUG-IN FREQUENCY EXTENDERS FOR FREQUENCY METERS, ] PLUG-IN FREQUENCY CONVERTERS, [ TIME INTERVAL MEASUREMENT PLUG-INS, TIME INTERVAL AND DUAL MEASUREMENT PLUG-INS, ] PRESET PLUG-INS, VIDEO AMPLIFIER PLUG-INS, PRE-SCALER PLUG-INS, FREQUENCY COUNTERS, FREQUENCY TO D.C. CONVERTERS, DIGIT-SET UNIVERSAL COUNTERS, [ DIGITAL RECORDERS, REMOTE INLINE INDICATORS, D.C. TO TIME CONVERTERS, ] HIGH SPEED DIGITAL VOLT METERS, TIME INTERVAL METERS, DIGITAL LIMIT DETECTORS, DIGITAL VOLT METERS, DIGITAL CLOCKS, ELECTRONIC COUNTERS, AUTOMATIC CHECKOUT EQUIPMENT, SINGLE AND MULTI-CHANNEL DATA PROCESSORS, VOLTAGE TO TIME CONVERTERS, ELECTRONIC DATA ACQUISITION SYSTEMS, [ ANALOG COMPUTERS, ] SUMMERS, INTEGRATORS, MULTIPLIERS, INVERTERS FOR ANALOG COMPUTERS, VARIABLE DIODE FUNCTION GENERATORS, COMPARATORS, DIGITAL LOGIC CONTROL MODULES, OPERATIONAL AMPLIFIERS, SUMMERS/INVERTERS, FUNCTION RELAYS, ELECTRONIC SWITCHES, FUNCTION SWITCHES, COEFFICIENT POTENTIOMETERS, FLIP FLOPS, GATES, POWER SUPPLIES FOR ANALOG COMPUTERS, [ ANALOG COMPUTER PROBLEM BOARDS, ] LINEAR AND ANGULAR SERVO ACCELEROMETERS, SERVO ACCELEROMETER POWER SUPPLIES, ELECTRONIC FILTERS FOR ACCELEROMETERS, INERTIAL STABILIZING SYSTEMS, ACCELERATION SWITCHES, VELOCITY SENSORS [ , VELOCITY PRESET ELECTRONICS MODULES, GYROS, TIME CODE GENERATORS AND TAPE SEARCH SYSTEMS ]