According to Shannon's source-channel separation theorem, the source coding and the channel coding operations should be performed independently. However, such a method does not exploit the nature of unequiprobable source output in a finite block regime so that it can not achieve good qualities in several scenarios in practical systems. In this study, we propose a JSCC strategy which takes into account the unequiprobable source output to attain better data quality than traditional methods. An adaptation is performed in order to map source code outputs to appropriate inputs of channel code. We also propose a greedy algorithm to construct parameters for the adaptation in polynomial time. Our simulation is performed on AMR compression to estimate the effect of our approach as compared to the traditional strategy. Using this approach we find significantly improved speech quality after transmission in both cases: transfer of only one AMR codec mode and transfer of all AMR codec modes