The enhanced variable rate codec (EVRC) is a standard for the "Speech Service Option 3 for Wideband Spread Spectrum Digital System," which has been employed in both IS-95 cellular systems and ANSI J-STC-008 PCS (personal communications systems). This paper concentrates on channel decoders that exploit the residual redundancy inherent in the enhanced variable rate codec bitstream. This residual redundancy is quantified by modeling the parameters as first order Markov chains and computing the entropy rate based on the relative frequencies of transitions. Moreover, this residual redundancy can be exploited by an appropriately "tuned" channel decoder to provide substantial coding gain when compared with the decoders that do not exploit it. Channel coding schemes include convolutional codes, and iteratively decoded parallel concatenated convolutional "turbo" codes.