Calibration Procedure for Electronic Counter, Hewlett-Packard Models 5243L, C02-5243L, C04-5243L, E05-5243L, H12-5243L, C27-5243L, 5245L(CP-722/U), C38-5245L, H78-5245L, 5245M, and H33-5245M, with Interval Timer 5262A and C04-5262A, and Prescaler 5252A.