This guide offers a complete reference on VoIP voice and Fax modules, including signal processing aspects, implementations, and mapping to the whole system. Covering both implementation and troubleshooting, it establishes end-to-end voice-Fax solutions, module description with proper interpretation, practical aspects, measurements, results, and FAQ. The coverage smoothes the way from PSTN to VoIP by depicting VoIP infrastructure with diagrams, architectures, and examples. Students and professionals will gain a detailed understanding of VoIP implementation with this accessible, uniquely integrated reference.