Why VoIP is replacing PSTN (Public Switched Telephone Network)? Fiber optic communication tutorial
The history of the traditional PSTN
The traditional PSTN (Public Switched Telephone Network) has continually improved since its creation by Alexander Bell. There are valid reasons why the PSTN exists in its current state.
What is Ring-Down?
At first, Bell developed a dial-down circuit, which means no numbers are dialed. Instead, a physical cable connected two phone devices. You just pick up the phone and the other person is directly on the other end and nothing rings.
Basically, this structure failed as more and more users joined the network. Since, according to this concept, you will need a cable between two people who want to make a phone call. With more customers joining, this became a messy mesh network that was very expensive and impossible to build and manage.
The beginning of the change
That was the moment when the concept of a switch came into play. Each user only needed one cable to connect to the central office switch, the switch can then connect the user to any other user.
Initially the switch was manually operated by a telephone operator. The operator connected the caller to whoever they wanted to call by manually connecting the voice path.
Later, the manually operated switch was replaced by electronic switches that were much faster and had much more capacity.
PSTN limitations
PSTN has really done a good job of changing voice calls, that is, until now. With more data traffic than voice traffic on the network, the traditional PSTN network simply isn’t flexible enough to keep up with new technologies and customer requirements. Here are some simple explanations.
1. Data traffic has exceeded voice traffic. The current state is: Data traffic is running on top of networks that were built for voice. However, data traffic has its own characteristics, which make it simply not efficient when running over a voice network.
The industry trend is to build networks with a data-centric approach. So all traffic including data, voice and video can run on this network.
2. PSTN is not able to keep up with new customer demands. PSTN was designed as a one-company show. Only PSTN equipment providers can develop applications for that equipment. With modern ever-changing demands, it is simply impossible for a single company to meet all the needs of all customers. A more open infrastructure is required that allows many vendors to provide applications.
3. The current PSTN cannot support data, video and voice together. On the PSTN backbone, the convergence of data, voice, and video has been going on for quite some time. However, it still takes some time to reach all households. With high-speed broadband access, such as DSL, cable, or wireless, the convergence of data, video, and voice in the home is finally taking place.
4. The PSTN was simply not designed to carry data traffic. Because bearer channels, call control, and service logic are closely linked in a closed platform, it is not possible to make minor changes that can improve audio quality.