Superseded by IEEE Std 269-2002.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.

The purpose of this standard is to describe practical methods for measuring the transmission characteristics of a telephone set by means of objective measurements using a test connection. Although the various methods generally produce similar results, some deviations can be expected depending on telephone characteristics. Measurement conditions should be noted when reporting results. 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. This standard is intended for measuring the transmission performance of conventional two-wire analog telephone sets and digital telephone sets. These telephone sets can be equipped with handsets or headsets using carbon or linear transmitters. This standard covers measurements over the frequency range most useful for speech, 100 Hz to 5000 Hz. This standard is not intended to be applicable to special devices such as noise exclusion transmitters, loudspea...