Revision Standard - Inactive - Superseded.Superseded by IEEE Std 269-2002. Practical methods for measuring the transmission characteristics of both digital and conventional to wire analog telephone sets by means of objective measurements on a test connection are described. The test results thus obtained may be used as a means of evaluating or specifying the transmission performance of a telephone set on a standardized basis. The measurements are applicable to telephone sets incorporating carbon or linear transmitters. Measurements are over the frequency range most useful for speech: 100-5000 Hz. The test methods are not intended to be applicable to special devices, such as noise-exclusion transmitters, distant-talking transmitters, insert-type receivers, or noise-exclusion receivers equipped with large ear pads. You will receive an email from Customer Service with the URL needed to access this publication online.