This document provides a comprehensive guide on building a simple virtual office PBX system using Teksip and Tekivr, detailing the necessary components like a VOIP gateway, soft IP phone, and the specific versions of the software needed. It outlines the configuration process for Teksip, Tekivr, and the VOIP gateway to facilitate call handling, routing, and automated responses using an IVR system. The document also includes configuration details and examples for establishing the system effectively within an office LAN environment.