377 / | HD | ELECTRICAL PULSE COUNTERS, PULSE DIVIDERS, OR SHIFT REGISTERS: CIRCUITS AND SYSTEMS |
27 | DF | SYSTEMS {21} |
28 | DF | .~ Identifying or correcting improper counter operation (e.g., error checking, monitoring; preventing or correcting improper counter operation) {2} |
30 | DF | .~.~ Preventing an inaccurate count as a result of an external condition {2} |
32 | .~.~.~ Power failure |