In recent years, SIP-telephony has gained immense popularity. What is this communication standard? How is the appropriate software and hardware solutions configured for the correct use of it? In what cases is such a connection more advantageous than the traditional one, carried out through a regular telephone? We will now explore these and other aspects.
Terminology
SIP-telephony - what is it? What are the distinguishing features of this technology? Is IP telephony the same thing? It all depends on the methodology for classifying communication standards, which we take as a basis. There are four main ones today.
According to the first, SIP and IP telephony are subcategories of a more global concept. What? Some experts call it "Internet telephony", others - "VoIP technology", from voice over IP - voice over IP, Internet Protocol. Based on this concept, IP-telephony has a distinctive feature - the closeness of communication technologies. In turn, the SIP connection is based on open connection protocols.
The second methodology implies that SIP communication is a special variant of a more capacious concept, which is IP telephony. In turn, if we are talking about closed connection protocols, then theirare usually named based on the brand affiliation of those software and hardware solutions that are offered to the end user. For example, Skype, Google Voice, etc. Thus, open technologies are SIP telephony.
The third interpretation says that both of these types in the process of natural development of the communications market actually represent the same group of technologies, namely those based on predominantly hardware solutions. Therefore, in most contexts they can be used as synonyms. In turn, they are opposed mainly to software communication methods - the same Skype and Google voice services.
The fourth interpretation, within which there is a distinction between the concepts of SIP and IP telephony, is based on the difference in order to build the appropriate communication infrastructures. As a rule, SIP standards allow you to organize typical telephone networks with a wide range of functions related to forwarding, using an answering machine, etc. IP telephony allows you to build an infrastructure with a wider range of capabilities. Thus, not only telephones and PBXs can be connected to the network, but also systems such as "smart home" or those devices that are usually classified as "Internet of Things".
Distinguishing Features of Technology
What is the unconditional distinguishing feature that characterizes SIP-type Internet telephony? Probably, this is the same openness, the use of free, flexible protocols. With this in mind, here are some answers to the question:"SIP telephony - what is it?":
- VoIP communication with open protocol;
- IP-telephony based on free technologies;
- predominantly a hardware solution (very similar to a regular phone);
- a system in which a typical "telephone" type of device works.
But at the same time, we take into account that each of these interpretations can be correct (as well as to have complaints from IT experts who adhere to other classifications that we have not indicated, but they exist). But the first point can be considered the basic criterion - where we are talking about the openness of communication technologies.
Why do I need SIP-telephony?
Having de alt with the features of such a technology as SIP-telephony (what it is, what are its distinguishing features), we can try to answer the question of why it is, in principle, needed. How is it better than standard telephone communication (if we talk about hardware implementations of this technology) or Skype, Google Voice (in relation to software solutions)? Experts highlight the following features of communication via SIP protocols:
1. Connection charges are generally significantly lower than for closed commercial applications.
2. More flexible configuration (in most cases) of SIP systems when it comes to corporate use. Using modern equipment and software, you can turn a SIP system into an analogue of a full-fledged PBX. At the same time, the cost of implementing the relevant solutions will be disproportionately lower.
3. Ability to receive incoming calls to a landlineroom. The same Skype is focused mainly on the Internet communication of users, each of which has a program loaded, and it works in the "online" mode. They do not have at their disposal a telephone number in international format (unless they have ordered a "virtual" one). You can call a phone that works in the SIP system both from a regular phone and from a cellular phone. There are two options for this. The first uses the access number provided by the SIP provider and a unique subscriber ID. In the second case, a "virtual" direct number is attached to the user's account, which looks exactly like a standard telephone number in international format.
It is noteworthy that the "virtual" number, or offered by the provider, does not have a real geographical reference. They may include a code specific to a certain country or city, but this will not mean at all that the subscriber must be in the corresponding coordinates.
Benefits of SIP telephony
Thus, the main advantages that SIP-telephony for home or office has, when compared with standard ("analogue") communication, are as follows:
- cheaper fares (and equipment in many cases);
- lack of "binding" to a specific place (you can communicate wherever there is Internet).
In turn, the advantages of SIP technologies compared to software solutions such as Skype are as follows:
- cheaper in many cases calls to regularphones;
- the ability to receive incoming calls from stationary devices.
How SIP telephony works
How does SIP telephony work? Setting up a SIP connection - is it difficult? The principles of both are very simple.
This type of connection works like this. The subscriber registers his account with a SIP telephony provider or provider. He gets at his disposal, as we said above, a personal number in the SIP system. As a rule, it is five digits (but there may be more digits). As soon as the subscriber connects to his account using a special program or a telephone adapted to SIP technology, he can make or receive calls.
As for outgoing calls, everything is simple here: you need to act as if the user had a regular phone in his hands (we dial the desired number in the international format). Receiving calls is a little more difficult. There are two schemes - with and without a virtual phone number. What is the difference? In the first case, we buy a number from the same provider or another provider specializing in their sale (or, more often, we “rent” it on a monthly fee basis), and then redirect it to a SIP number. The structure of the latter looks like this: first comes the access number indicated in the international format, which belongs to the provider. For example, this one: +7 495 7776675 (nowadays popular Zadarma). Then - "additional" and at the same time personal number of the subscriber. In the case of Zadarma, it is usually five digits. Pause marks are usually put between the main and second number in the program settings of redirection - p.
You can call through a virtual number - then the call will be automatically redirected to your account. Or we use the provider's access number, plus an extension - the one that is tied to the subscriber's account. Provided, of course, that the person is online through a program or device that supports SIP calls.
SIP telephony features
How can useful SIP telephony options be put into practice? There are a lot of options here. Consider an example where a SIP number can be used on a business trip abroad as a great alternative to expensive calls using a regular phone.
SIP operators operating in Russia are establishing close cooperation with foreign ones. And therefore, their subscribers can take full advantage of the appropriate communication technology while abroad. This is possible, in particular, due to the introduction into international practice of such an element as the SIP server code.
SIP server code
What is this? The fact is that it allows a Russian subscriber located on the territory of another country to call his home using the number of a local provider, and not one that operates in the Russian Federation.
A simple example. We are, say, in Italy. Suppose we need to call a friend's SIP number in Russia (provided that only a landline, for example, a hotel phone, is at hand). We can make a call in two ways:
1. Dial a friend's number using a Russian ISP access code. If this is Zadarma, then the numbers are as follows: + 7 495 7776675. And then enter the five-digit number of the subscriber. But this is likely to cost us dearly. Calls from Western Europe to Russia are not cheap.
2. Call a friend using a similar access number instead of a Russian access number - but for a local provider. And in combination with Zadarma SIP server code. You can find out the access number of the local provider by using the resources of the corresponding direction - there you can indicate the country and city where we are located. Suppose we are in Turin. And then the appropriate option would be: +39-011-19887800. We will find out the SIP server code for Zadarma there, in the catalog. It has four digits and is quite easy to remember - 9791.
How to call? First, we dial the Turin access number. Then we maintain a short pause and enter the Zadarma SIP server code. And after - the five-digit account number of our friend.
International call for free
A very important point that worries a person who has turned his attention to such technology as SIP telephony is call rates. What will they be? Most likely the lowest. Since we are calling from a hotel in Turin to a number in the same city, the connection will most likely be free. Redirection from the Italian access number to the Russian code of the SIP server, in accordance with inter-corporate agreements, is not charged. An incoming call to a friend's number is probably also free (as long as it doesn't involve forwarding). As a result, we either do not pay for the call at all, orwe pay a very small bill for a local call to a Turin number, which the hotel can put up for us. We are dealing with a unique phenomenon: we have at our disposal international, and, moreover, with a high probability free, SIP-telephony.
iNUM type numbers
We said above that it is possible to reach a subscriber without using the provider's access phone, which may not seem very convenient, by using a "virtual" number. However, since relatively recently, a third option for making calls has also been available to Russian users. It implies the use of the "global" iNUM telephone number. What is its specificity?
The iNUM number was put into use by the international organization ITU. In principle, it can be considered a kind of virtual number. It always starts with the code +883 (510), and this rule is the same for all subscribers connected to it, regardless of their citizenship and country of actual location. iNUM numbers can be issued by local SIP telephony operators.
It should be noted that the charging of outgoing calls to iNUM from fixed phones is very unattractive. In many cases it is cheaper if the person has a national telephone number. And therefore, it is advisable to use the option with iNUM only if the caller uses a program for SIP telephony or a SIP device. The ideal option is if both are connected to the same provider. But even if this is not so, it is not critical. Tariffs for such callsproviders are not as high as those of fixed-line operators such as MTS or Rostelecom. SIP telephony, as we said at the very beginning, is characterized primarily by lower communication costs compared to traditional technologies. In some cases, the tariffs for calls to iNUM numbers are quite low for VoIP services - the same Skype, Google and their numerous analogues.
SIP telephony and hardware solutions
Let's study such an aspect as using SIP communication capabilities using hardware methods. What solutions can be used here? Experts name the following three groups:
1. Use of SIP applications for mobile devices. In this case, the hardware implementation of the technology will be a smartphone or tablet. All that is needed for the implementation of communication sessions is a stable access to the Internet. In this case, the speed does not have to be high. As a rule, a channel of 100-200 Kbps is enough for high-quality voice communication. Wi-Fi connection (provided that it is "distributed" by a router connected to a DSL or fiber optic channel), as well as 3G and 4G standards will give the best stability.
2. Use of SIP-devices. Outwardly, they look exactly the same as the usual analog phones. Setting up SIP access is done (despite the lack of software interfaces in most cases) quite easily - according to the attached manual, as well as instructions from the provider's website. When choosing the appropriate machine, it is important to purchase one that is compatible with the access technology.the Internet. Most modern phones use Wi-Fi.
3. Using SIP adapters. These devices provide the function of an "intermediary" between conventional, analog, telephones and an Internet channel (most often in the form of the same Wi-Fi connection). Some of their models support the simultaneous connection of several telephone sets.
Of course, you can use a lot of possibilities of SIP-telephony with the help of a computer connected to the Internet. Appropriate programs allow you to make and receive calls while communicating with other SIP subscribers or people using a regular phone.
The main condition for the functionality of all three communication formats is the presence of a stable Internet connection. The best option is one of the modern wired technologies. You can also use a mobile device in the coverage area of a mobile operator with a good signal level and support for high-speed Internet access standards.
It should also be noted the versatility of such technology as SIP-telephony. That this is not only a communication standard, but also a full-fledged mechanism for organizing communication within a large (and not so) office, at home, an excellent tool for saving money when traveling abroad, for communicating with friends and business partners in other countries - you will see right away!
Most modern providers offer options not only for receiving and forwarding calls, but also for recording voicemessages, distribute incoming calls to addresses, use answering machines, enable "callback" functions and other useful features. At the same time, the quality of communication in most cases is not inferior to what is achieved on the most modern digital telephone lines.
