With so many varieties of communications technologies as to date, many of us including engineers are still confused how to understand its basic operation and why do some operators prefer to implement one technology over the other. Well, I had also experienced the same when I first jumped into this industry and to make things worse, we tend to go so details at one technology and when its time to explain their general concept.....we just couldn't do it. You know why? Because we ourselves don't understand the overall concept of telecommunications. Well, my next postings will be a series of articles about this industry that I want to share with you guys. Most of them are from other sites that I handpicked, just to make sure you will only read the right material for you to grab the basic idea.