en 3-Control in Computer & Communication Control in Computer & Communication Networks Research Paper Research Paper Accurate and reliable time is necessary for financial and legal transactions, transportation, distribution systems, and many other applications. Time synchronization protocols such as NTP (the Network Time Protocol) have kept clocks of such applications synchronized to each other for many years. Nowadays there are many commercial GPS based NTP time server products at the market but they almost have a high price. In this paper we are going to use a low cost GPS engine to build a time server to provide time synchronization with accuracy of a few milliseconds. This time server is relatively very cheap and it can be used in almost all typical applications. We also proposed a software based NTP time server implemented in MATLAB as well. Time Synchronization,Time Synchronization Protocols,NTP (the Network Time Protocol),GPS Timing,Computer Network,Time Server, 206 216 http://ijeee.iust.ac.ir/browse.php?a_code=A-10-222-4&slc_lang=en&sid=1 M. H. Refan refan@mapnaec.com 180031947532846001999 180031947532846001999 Yes Shahid Rajaee University H. Valizadeh valizadeh65@gmail.com 180031947532846002000 180031947532846002000 No Shahid Rajaee University