How is a VoIP call made?

VoIP has been around for quite some time now – in fact it started in the 90s – but has become part of the mainstream only in recent years. This decade has seen an explosion of the VoIP ecosystem, from manufacturers to service providers scrambling to fulfill rapidly growing demand around the world. Both the consumer and enterprise VoIP segments have seen significant changes and are barely recognizable from their humble beginnings.

Being able to talk to anyone in the world just by dialing a number has been part of the human experience for decades but VoIP brings a significant upgrade to that. However for such a significant upgrade, the actual experience for the user has not changed. This is surprising largely because most new technology changes the workflow or processes in some manner. To understand the changes and similarities between VoIP and the older PSTN, we need to learn about what exactly VoIP is. So if you’re wondering “How is a VoIP call made?”, this article is for you!

How A Regular Call Is Made

The older generation PSTN was largely analog – physical copper wires connected both parties allowing them to talk. The network utilized TDM circuit technology in order to maintain an open connection between the caller and the receiver for the duration of the conversation. When the user picks up the phone and dials a number, the call is routed through a switch at the carrier office through to its destination.

For long-distance and international calls, a number of different interconnected switches could be involved to span the distance. The switches that control call routing have long since been digitized and automated but the basic technology, infrastructure and process of connecting users did not change much until the arrival of VoIP.

What is VoIP?

Voice over Internet Protocol has its roots in the Internet community rather than telecommunication standards. What started out as a hobby for a handful of people is now quickly on its way to being the default standard for real-time voice communication. The basic premise of VoIP is that audio calls can be treated the same as other forms of data on Internet such as email, images, text, documents etc.

But as the human voice is made up of analog signals, it has to be first converted into data packets that can be routed over the Internet instead of copper lines. VoIP combines many standards and protocols in order to transmit voice calls over the Internet, thus eliminating the need to maintain separate networks and infrastructure for voice and other forms of data.

How A VoIP Call Is Made

In a VoIP deployment, users make calls just as they would normally by picking up the phone and dialing a number. Connecting to the other party, setting up the individual session and managing the parameters of that particular session are all managed by the Session Initiation Protocol (SIP). The person’s voice is converted into data packets by audio codecs and then forwarded to the destination.

Rather than having to maintain an open circuit that spans the distance separating the callers, VoIP utilizes packet switching technology to send the individual packets on different routes. Each packet will make its own way to the destination and most of them may not even arrive in the same order in which they were sent. When they reach the other side, they are rearranged back into the original order and then converted into analog sound by audio codecs again.

The process might sound long and complicated when describing it in text but in reality, it doesn’t take more than a few seconds as it is all accomplished by electronic equipment and computers.

Why has VoIP become so Popular?

VoIP started out as a way for people to circumvent long-distance and international calling charges by their phone operators. Since the data was being sent over the Internet connection which was already paid for, users didn’t have to pay extra charges for making a call. After all, you don’t have to pay extra for sending videos instead of images, do you? As long as both parties had the VoIP software installed on their computers and the requisite hardware (speakers and mic), voice calls were basically free regardless of the distance.

Although price was one factor aiding the popularity of VoIP, another was the greater role being played by the Internet in all aspects of human activity. As broadband connectivity expanded across the globe, consumers and enterprises started conducting more transactions and workflows over the Internet instead of other channels. Over the last decade, many activities like banking, shopping, collaborating with others, gaming etc. moved online. It was perhaps inevitable that making calls would also follow shortly.

The Future of Making Calls

At present we are in the transition phase of moving over from the PSTN to VoIP. In many countries, the bulk of calls are still made through the reliable PSTN but that is quickly changing as more regions come online. VoIP has already introduced more features to consumers and businesses than was ever thought possible. Behind the scenes, major telecom operators around the world are already upgrading their infrastructure to support VoIP in some form or the other.

To make a VoIP call, most people still need specific equipment such as SIP compatible phones, ATA adapters, mobile devices or a computer with VoIP software etc. The next step for VoIP calling would be to eliminate the requirement of extraneous equipment. In the future we might not even need this much as WebRTC – another revolution in real-time communication – is steadily making progress. With WebRTC compatible Internet browsers, users would need nothing else to make and receive phone calls.

The telecom industry is changing at a faster rate than it has ever done and with every passing year, some fresh innovation is introduced to the market. Even after the introduction of VoIP, voice calls are still not treated the same as other forms of media. But it won’t be long before all calls will be VoIP calls and there won’t be much of a difference in sending an email, starting a videoconference or calling someone as they will all travel on the same Internet.