Nowadays, with the development of the Internet into everyday life of a man breaks into an increasing number of new products and enhancements, coupled with telecommunications technology and communications. All of this is due to the many benefits that accrue to the subscriber, not a matter for which he needed this kind of telephony. Whether it is the private use of telephones or office, in any case, the client receives the highest quality, using local, long distance and international communication, and thanks to cheap cost of routing a call, the customer gets a very flexible and affordable tariff plans.

In addition, users of modern digital telephony are supported by any type of technology, whether Digital Enhanced Cordless Telecommunications (DECT), Wireless Local Area Network (WLAN), Internet Protocol (IP), Time Division Multiplexing (TDM) or Session Initiation Protocol (SIP), functions of a regular phone, and more importantly – the opportunity to transmit voice, video or data. In this case, because if you call with IP-phones is not activated international (national carrier), the cost of such calls is significantly lower than with traditional phone call.

Another important advantage is that – safety. Although most consumers are not IP Telephony but it is relatively easy to install plays such calls, or even change their content, but all are the introduction of VoIP protocol can significantly complicate the interference in the system. In addition, although absolutely secure methods of communication and does not exist, it is in IP telephony which can produce complex multi-level encryption, providing complete anonymity of all VoIP traffic with I2P Network (router software).

But, as in all the results of progress, and here, too, was not without flaws. When using IP Telephony, coding speech information leads to distortion and deterioration of the quality of communication and speech. Experts believe that this happens in case of packet loss at the time of transmission networks or due to slow Internet speed, as well as if it involved potentially exceeding the time required for delivery of a package that carries voice data. All this requires careful work to optimize the delay in the network and algorithms for recovering lost packets.

However, in spite of some shortcomings of digital telephony, it is considered the fastest and most reliable way to send data.

Few years back, the Internet users discovered that a normal voice of humans can be encoded and thus it became one of the kinds of data which can be sent through the Internet anywhere, any corner of the world using the Internet Protocol (IP).

In order to convert digital voice data via the conventional telephone network to the Internet, creating a new device something that will let you to move from circuit switching to packet switching (so called “Voice Gateways”) was very much necessary. Using that technology a telephone conversation was obtained on the Internet, to transmit it at any long distance and hear anywhere in the world via the regular telephone network. This technology is known as IP Telephony or more incisively, VoIP.

IP-telephony (primitively known as VoIP an abbreviation for Voice Over Internet protocol or Voice Over IP) – a protocol designed for Voice over the Internet or other networks with similar organizations, such as local city networks, or networks of a single institution or company.
Although it is often the term IP Telephony refers to a particular implementation of the protocol or service providers, not the protocol itself. Now at most major Internet service providers, IP Telephony is available in a standard set of services along with an Internet access, VoIP Hosting, etc.

The first experiment with network voice protocol was held in 1973 by the network ARPANET. But, until the high-speed communication channels IP telephony did not have a large spread.

A phone call over IP rather have a computer connected to the network, a microphone with a headset and special software to transfer data over the network, as well as the possibility of a direct connection to IP-based network. In order for a subscriber to receives the call must have the same set of hardware and software that expects a call from the outside.

Over time, there were special IP phones, almost no different in appearance from conventional mobile and is usually connected via USB to your computer. The principle of operation is not much different from the microphone with headphones, but as a rule, USB phones have some additional useful features, for example, have built-in sound card that allows them to use even on computers without sound card, and also provides the opportunity to listen to music while negotiation.

If the local network is connected to the telephone, then a VoIP phone, you can call on a mobile or land-line phones and vice versa. With the development of IP telephony appeared appropriate gateways that are connected to the Internet, and to the exchange, which brought together the virtual telephone network with the traditional. Now one can easily acquire direct dial phone number when calling to be the caller, and IP phone. A cheaper option, popular among providers – using a local number with additional calls for each subscriber network. This option is very useful for organizations and is often much cheaper than buying an extra line.

For calls within a VoIP traditional network numbers are not commonly used. Instead, you have to login service that provides communications to subscribers. Of the most popular services can be noted is Skype. The service has several advantages over direct calls from computer to computer. The main thing – it is not necessary in the real IP for both subscribers, making calls is very affordable with VoIP dedicated servers.