The purpose of this Recommendation is to describe a subjective listening test method which can be used to evaluate the speech quality of Digital Circuit Multiplication Equipment (DCME) or packetized voice systems. This Recommendation is intended for use with DCME systems, such as those described in Recommendation G.763, which use digital speech interpolation (DSI) techniques. For subjective test evaluations of DCME systems not using digital speech interpolation techniques, described in Recommendation G.726 [40, 32, 24, 16 kbit/s Adaptive Differential Pulse Code Modulation (ADPCM)], use Recommendation P.83.