Operators of mobile and fixed communication usually offer their users attractive conditions for calls «inside the network», but when it comes to communication with distant cities and foreign countries, the cost of such services can seriously damage the wallet. However, the solution to this problem has long existed, and it is called
This is a technology of voice communication, in which computer networks, network communication protocols and special technological methods are used for conversations. In simple words, the Internet (or a local network, for communication within the company or enterprise) is used to make calls, which makes their cost significantly smaller.
The date of the first appearance of technology can be considered 1993. It was then that the American Charlie Klein created a unique program of his kind called Maven, which allowed to broadcast voice over the Internet without delays. In 1994, Maven implemented in one of the first
In 1995, VocalTec entered the global consumer market with the Internet Phone for Windows application. Thanks to the use of all the advanced technologies at that time (conversion of digital signals, use of codecs and routing protocols), the level of delays and quality loss has significantly decreased. The rest of the companies immediately evaluated the market’s prospects and began working on their own analogues.
1996 is considered the official birthday of
It is noteworthy that Russia was one of the first countries in which the gateway for
When it goes about IP telephony, terms are often used, which may not be particularly understandable for the average person. Let’s figure it out together.
- Gateway is a device that is an «intermediary» between a telephone line and a computer network, that is, it performs the function of pairing them.
IP-networks— a system of interconnected subnets, providing the interaction of autonomous systems, which in turn are combined with the help of routers.
- VoIP is a technology for voice transfer over the Internet and / or computer networks. The definition is very similar to IP telephony, but the key difference is the fact that in VoIP, data transmission does not need to be connected with people’s communication. That is, VoIP can be used, for example, for video surveillance, online broadcasts on the Internet, etc.
- SIP is a session management protocol that supports voice, multimedia, instant text messages, and the like. In VoIP, it can be responsible for connecting and disconnecting subscribers, as well as responding to changes in real time (for example, including redirection).
Principles of IP Telephony
In traditional telephone communication, where the only purpose is to talk directly between subscribers, a special telephone exchange is responsible for the connection. That is, there is a dedicated connection, through which the voice is transmitted over the telephone line. However, voice communication over the Internet works differently.
First of all, the telephone signal is transmitted to the gateway. If the signal is not digital, then the process of digitizing it is mandatory. After that, the data is compressed, divided into packets and transmitted to the endpoint using the TCP / IP protocol. At this point, IP packets are decoded so that the recipient subscriber can hear the original signal (voice).
All operations occur almost simultaneously, because users do not notice any delays or interrupts of sound. However, there are also bad providers, who still have similar problems. The quality of communication also depends on the speed and reliability of connecting users to the Internet.
Depending on the method of communication,
Computer-to-computeris the simplest option, which requires a special program (Skype, SIPNET, etc.) and a working headset for the computer; Computer-phone— almost no difference from the previous method, except that one of the subscribers is not tied to the computer — he uses a regular phone; Phone-to-phone— except for individual services, the service of IP-telephonyis not neglected even by ordinary cellular operators, which helps reduce the cost of calls;
- Surf & Call — ability to make calls directly from the site, which is often used in commercial companies.
The main advantage is that such a link is profitable in financial terms. And both for ordinary subscribers, and for large operators. Technologies of voice packets compression allow to use the power of telephone lines optimally and without unnecessary loads, and the globalization of Internet access constantly increases the range of potential users of the service.
To date, it is possible to connect
Internet telephony is often used in corporate networks. In this case, the communication functionality lends itself to flexible settings and constant improvements. Finally, thanks to this connection, you can call without leaving your computer, which can be a very significant factor for business people.
Our service uses a hybrid technology, which uses both telephone and cellular lines, and