IP Telephony cloud pbx concept, telephone device with illustration icon of voip services and networking data center on background

The VoIP is a technology that allows to use the power of the Internet Protocol to access the telephone network. A solution that is part of the movement towards all IP. Why do you want to rely on the Internet for telephony, and how does it work? We will answer all of these questions … and many more.

Some time ago, it was difficult to find one’s way in the “jungle” of communication networks. Each operator used its own technologies: switched telephone network (PSTN) to make and receive telephone calls, the Transpac network for Minitel and banking services, nanoretwork in classrooms, etc.

The revolution came with the rise of TCP / IP . It is quite simply the Internet protocol , which has spread very quickly within companies. They were thus able to abandon the use of proprietary protocols in favor of this rising standard, in order to create local networks , or LANs, capable of connecting all offices.

With the expansion of the Internet, all of these computer networks have gradually been linked together. This is why the Internet is often referred to as the network of networks . It is a multiservice communication infrastructure, common to all. Like a highway, the Internet can be used freely. You do not pay – in general – for the use of Internet services, but for access to the network, to which you are connected by an Internet Service Provider , or ISP.

The very logic of the Internet, that of being a global, open and shared information highway, means that operators quickly adopted it to carry telephone communications.

How does VoIP telephony work? 

To make calls through the Internet, it is necessary to adapt the “voice” signal to a network where everything essentially passes in the form of digital data packets . To achieve this, Net experts have quite simply set up so-called Voice over IP, or VoIP, protocols .

However, it is important to distinguish between VoIP and VoIP Telephony:

The  Voice over IP “simple” allows two people to make calls over the Internet, but that does not necessarily mean access to the conventional telephone network. 

For example, two people who communicate through Skype speak to each other without going through the traditional telephone network, the PSTN: it is Skype which ensures the communication, directly through the Internet. In return, communication is only possible if each party has Skype on their computer, the protocol used here being proprietary. It is therefore not VoIP telephony, but simply VoIP.

On the other hand, the landline telephone that you plug into the back of an Internet box is a practical application for VoIP telephony . The terminal uses the Internet for data transfer, but it can call any telephone number connected to the PSTN network, and vice versa . And the person trying to reach you does not need to use VoIP telephony themselves. Only VoIP telephony, or IP telephony (ToIP), is capable of providing access to the traditional telephony network.

SIP, the reference protocol for VoIP telephony

The VoIP protocols are numerous. To route voice calls over the Internet, operators have long used H.323. This open standard created by the ITU (International Telecommunications Union) transmits communications including audio, images and data over the Internet.

H.323 has gradually given way to another open protocol, SIP ( Session Initiation Protocol ). SIP appeared at the end of the 1990s and makes it possible to manage all types of communications in real time, text, voice or video. This protocol is standardized by the Internet Engineering Task Force (IETF ), which created most of the Internet’s protocols. 

However, a VoIP protocol is not enough to access IP telephony. Operators are also needed to connect with the public telephone network. This is called SIP trunking . The SIP trunk is used to match a SIP line with a conventional telephone line, represented by its telephone number. It is the SIP trunk that transforms VoIP into VoIP telephony.

How to access VoIP telephony in business? 

Ultimately, the French switched telephone network (PSTN) is set to disappear , in favor of the Internet alone. The question of whether or not to switch to a VoIP solution therefore does not arise. Work in your company will then begin by setting to find voip phone ip address infrastructure within your premises: presence of network outlets in each office and connection to the Internet, provided by an ADSL, SDSL or fiber optic line .

Once the connection is active, several VoIP solutions are available to professionals. For those who only need a few independent telephone lines, it is quite possible to connect SIP-compatible VoIP telephones to the company’s network sockets, then to associate them with traditional telephone lines, via a subscribed subscription. from a telephone operator that can provide SIP trunk.

But that would miss out on the benefits of a business telephone system based on a private branch exchange (PBX) , or hosted in the cloud (Centrex IP) . The latter offers many advantages:

  • a single number to call the company, linked to a switchboard or an interactive voice greeting;
  • internal stations linked directly to each other, with call transfer and interception;
  • support for simultaneous calls and three-way conversations;
  • personalized voicemail and music on hold.

Better still, the new fixed telephony contracts associated with VoIP often offer unlimited communications. An asset for lowering the amount of telephone bills.

Read More: How eCommerce Website Development Benefits Your Business

Which telephone set should I use? 

As for VoIP-compatible telephones, the models range from traditional handset, with or without cord, to full standard . Telephone octopuses will be suitable for conference calls, from a meeting room for example.

Let’s not forget about softphones either . Importantly, they remain usable outside the walls of the company, where they can continue to receive and send calls, as in the office. They therefore allow complete mobility, and will facilitate your future remote teleworking sessions.

As we have just seen, one of the advantages of VoIP telephony is that it also makes it possible to pave the way for unified communications solutions , and fixed-mobile convergence!

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