This document defines the methods of measurement to test performance of the Project 25 (P25) enhanced vocoder. The measurements can then be compared to performance specifications to meet the voice and audio quality objectives defined by this standard for the P25 enhanced vocoder. The P25 enhanced vocoder is a dual-rate vocoder with a fullrate mode for interoperability with P25 Phase 1 equipment and a half-rate mode for interoperability with P25 Phase 2 equipment. The test methods and performance specifications are defined for both modes of operation. The test methods and performance specifications are defined for both the encoder and the decoder components of the P25 enhanced vocoder. The P25 enhanced vocoder to be tested shall be applicable to both a radio, and a fixed infrastructure device such as a console.