(This issue of Network Road covers the following topics: 1. Overview of voice development, introduction to SIP protocol, introduction to DPL, call signal tone, use of Radius protocol in voice, classification and use of voice compression coding technology and other theoretical basic knowledge of voice; 2. Knowledge of typical use of SIP, overview of unified communication, combined use of voice and wireless network, etc. knowledge of voice use and expansion; 3. Preliminary configuration of Abacus5000, Abacus test solution; FAXoverIP theory and test introduction, VoIP voice quality test Knowledge of other voice testing technologies; 4. Prospects of voice technologies such as NGN overview;)