ITU-T Recommendations

This Recommendation was generated to provide planning guidance for designers of networks that would form part of an international telephone connection. For example, guidance on the maximum number of A/D conversions and the impairment impact of waveform type codecs, in the form of planning rules, was provided. This method has been referred to as the the Quantization Distortion Method. However, these planning rules did not adequately address the impairments of non-waveform encoders as well as a number of other impairments. This Recommendation has been reissued to make the document more useful by the retention of the Quantization Distortion Method and the incorporation of a new planning method, called the Equipment Impairment Factor Method. The Equipment Impairment Factor Method allows the impacts of: non-waveform codecs, non-optimum overall loudness rating, talker echo, and speech difficulty associated with long one-way delay to be evaluated.