Irfan AsifUsman Asif2026-02-012026-02-012025-02-12https://escholar.umt.edu.pk/handle/123456789/19483This report aims to describe the complete process that was followed while developing a telephone service using VoIP through Asterisk (an open-source PBX). Our project aims to create a telephony system that allows subscribers to make calls using softphones (or computers) for communication via our service. Furthermore, our system also allows users to make and receive GSM and landline calls on their softphones. Hence, our solution is not only cost-effective but also very user-friendly. We have used Asterisk to act as the exchange for our main servers. Asterisk is an open-source private branch exchange (PBX) implemented in Linux. It has the facility to connect to the local telephone exchange or PSTN and other Asterisk exchanges. We have implemented a dial plan on our main server that allows our subscribers to dial the number they desire to connect with. The voice traffic generated after the establishment of a connection is transmitted using voice over IP (VoIP). This document explains the requirements, analysis and design, implementation issues, and testing process of the project, and concludes with future work that can be done in the direction of this project.enThesis