Mission critical situations depend on wireless communication. It is becoming increasingly popular to connect Land Mobile Radio (LMR) networks such as APCO Project 25 and Digital Mobile Radio (DMR) systems with commercial cellular LTE networks. This can provide commercial and public safety users with more ways to communicate, while improving overall coverage areas, decreasing system costs and taking advantage of Internet data accessibility. Yet, not all digital wireless systems are compatible with one another if they do not share the same voice coding technology, known as a vocoder. Most modern LMR networks use the AMBE+2 ™ vocoder whereas cellular LTE networks use the Advanced Multi-Rate (AMR) vocoder. Transcoding from one vocoder to another can lead to the loss of intelligibility, increase delay and interfere with communications security, and should be avoided in favor of utilizing the same vocoder end-to-end in a communication system.