In recent years, SIP telephony has gained immense popularity. What is this communication standard? How is the appropriate software and hardware solutions configured for their correct use? In what cases is such a connection more advantageous in comparison with a traditional one via a regular telephone? Now we will study these and other aspects.
Terminology
SIP telephony - what is it? What are the distinguishing features of this technology? Is IP Telephony the Same? It all depends on the classification methodology for communication standards, which we take as a basis. There are four of them today.
According to the first, SIP and IP telephony are subcategories of a more global concept. Which one? Some experts call it "Internet telephony", others - "VoIP technology", from voice over IP - voice over IP, Internet protocol. IP-telephony has, based on this concept, 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-connection is a private version of a more capacious concept, which is IP-telephony. In turn, when it comes to closed connection protocols, they are usually called based on the brand name of those software and hardware solutions that are offered to the end user. For example, Skype, Google Voice, etc. Thus, open technology is SIP telephony.
The third interpretation says that both of these types in the process of natural development of the communications market represent virtually the same group of technologies, namely those that are based primarily on hardware solutions. And therefore, in most contexts they can be used as synonyms. In turn, they are opposed mainly to software communication methods - the same voice services Skype and Google.
The fourth interpretation, in the framework of which the distinction is made 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 call forwarding, answering machine, etc. IP-telephony allows you to build an infrastructure with a wider range of capabilities. So, not only telephones and automatic telephone exchanges can be connected to the network, but also systems such as “smart home” or those devices that are usually classified as “Internet of things”.
Distinctive features of technology
What is the undoubted distinguishing feature that characterizes SIP-type Internet telephony? This is probably the same openness, the use of free, flexible protocols for configuring. In this regard, we give the answers to the question: "SIP-telephony - what is it?":
- VoIP communication with an open protocol;
- IP-telephony based on free technologies;
- mainly a hardware solution (very similar to a regular phone);
- a system in which a typically “telephone” type of device is operated.
But at the same time, we take into account that each of these interpretations can be correct (as well as have complaints from IT experts who adhere to other classifications that we did not indicate, but they exist). But the first criterion can be considered the basic criterion - where it comes to the openness of communication technologies.
Why do I need SIP telephony?
Having dealt with the features of a technology such 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. Why is it better than standard telephone communications (if we talk about hardware implementations of this technology) or Skype, Google Voice (in relation to software solutions)? Experts highlight the following communication features through SIP protocols:
1. Connection tariffs are usually significantly lower than when using 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 the SIP-system into an analogue of a full-fledged PBX. At the same time, the cost of implementing appropriate solutions will be disproportionately lower.
3. The ability to receive incoming calls to a landline number. The same Skype is focused mainly on the Internet communication of users, each of whom has downloaded the program, and it works in the "online" mode. They do not have a telephone number in international format (unless they ordered a “virtual” one). You can call a phone that runs in a SIP system from a regular device or from a cell phone. There are two options. In the first, the access number provided by the SIP provider and the unique identifier of the subscriber are used. In the second case, a “virtual” direct number is attached to the user’s account, which looks exactly like a standard telephone in the 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 specific country or city, but this will not mean that the subscriber must be in the appropriate coordinates.
Benefits of SIP Telephony
Thus, the main advantages that SIP-telephony has for home or office, when compared with standard ("analog") communication, are as follows:
- cheaper rates (and in many cases equipment);
- the 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 ordinary phones;
- the ability to receive incoming calls from stationary devices.
Principles of SIP Telephony
How does SIP telephony work? SIP connection setup - is it difficult? The principles of both are very simple.
This type of connection works like this. The subscriber registers his account with the 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-digit (but there may be more digits). As soon as a subscriber connects to his account using a special program or a telephone set adapted to SIP technology, he can make or receive calls.
As for outgoing calls, everything is simple: you need to act as if you had a regular phone in the hands of the user (we dial the desired number in the international format). Reception of calls is a little more difficult. There are two schemes - with and without a virtual telephone number. What is the difference? In the first case, we buy a number from the same provider or another supplier specializing in their sale (or, more often, we rent it on a monthly fee), and then we redirect it to a SIP number from it. 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: +7 495 7776675 (now popular Zadarma). Then - the "extension" and at the same time the personal number of the subscriber. In the case of Zadarma, it is usually five-digit. Between the main and the second number, pause signs are usually placed with redirection software settings - p.
Thus, you can call through a virtual number - then the call will automatically be 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 a 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. Consider an example where a SIP number can be used on a business trip as an excellent alternative to expensive calls using a regular telephone.
SIP-operators working in Russia establish close cooperation with foreign ones. And therefore, their subscribers can use all the advantages of the corresponding communication technology, while abroad. This is possible, in particular, due to the introduction of such an element as the SIP server code into international practice.
SIP Server Code
What it is? The fact is that it allows a Russian subscriber located in the territory of another country to call his home using the number of the local provider, and not that he is operating in the Russian Federation.
A simple example. We are located, say, in Italy. Suppose we need to call a friend’s SIP number in Russia (provided that you have only a landline, such as a hotel, telephone) at hand. We can make a call in two ways:
1. Dial a friend's number using the Russian provider access code. If this is Zadarma, then the numbers are: + 7 495 7776675. And then enter the five-digit subscriber number. But this, most likely, will cost us dearly. Calls from Western Europe to Russia are not cheap.
2. Call a friend using a similar access number instead of the Russian one - but for the local provider. And in combination with the Zadarma SIP server code. The access number of the local provider can be found by using the resources of the corresponding direction - there you can specify the country and city where we are. Suppose we are in Turin. And then a suitable option would be: + 39-011-19887800. We find out the SIP server code for Zadarma in the same directory. It is four-digit and quite easy to remember - 9791.
How to call? First, dial the Turin access number. Then we hold a short pause and enter the Zadarma SIP server code. And after - a five-digit account number of our friend.
International call for free
A very important point that excites a person who has turned his eyes to technology such 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 is likely to be free. Redirection from the Italian access number to the Russian SIP server code, in accordance with inter-company agreements, is not charged. An incoming call to a friend’s number is probably also free (if it doesn’t use redirection). As a result, we either do not pay for the call at all, or we pay a very small bill for a local call to the Turin number that the hotel can give us. We are dealing with a unique phenomenon: we have international, and moreover with high probability, free SIP-telephony.
INUM type numbers
We said above that it is possible to reach the subscriber without using the provider's access telephone number, which may not seem very convenient, using a "virtual" number. However, since relatively recently, the third option for making calls is also available to Russian users. It implies the use of a “global” iNUM telephone number. What is its specificity?
The iNUM number is entered 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 tariffing of outgoing calls to iNUM from landline phones is very unattractive. In many cases, it’s cheaper if the person has a national phone number. And therefore, it is advisable to use the option with iNUM only if the caller uses the SIP-telephony program or 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. The tariffs for such calls from providers are not as high as those of fixed-line telecom 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 many analogues.
SIP telephony and hardware solutions
We will study such an aspect as using the capabilities of SIP-communication using hardware methods. What solutions can be involved here? Experts name the following three groups:
1. Using SIP applications for mobile devices. In this case, the hardware implementation of the technology will be a smartphone or tablet. All that is necessary for the implementation of communication sessions is a stable access to the Internet. However, the speed does not have to be high. As a rule, a channel of 100-200 Kbps is sufficient for high-quality voice communications. The best stability will be given by a 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.
2. Use of SIP devices. Outwardly, they look exactly the same as the usual analog phones. Configuring SIP access is done (despite the absence 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 device, it is important to purchase one that is compatible with Internet access technology. Most modern phones use Wi-Fi.
3. Using SIP adapters. These devices provide an intermediary function between regular, analog, telephones and the Internet channel (most often in the form of the same Wi-Fi connection). Some of their models support the simultaneous connection of several telephones.
Of course, you can take advantage of so many features of SIP-telephony and using a computer connected to the Internet. Corresponding programs allow you to make and receive calls while communicating with other SIP-subscribers or people using a regular telephone.
The main condition for the functionality of all three communication formats is the availability 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 standards for access to the Network.
It should also be noted the versatility of technology such 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 it right away!
Most modern providers offer options not only for receiving and forwarding calls, but also for recording voice messages, distributing incoming calls to addresses, using answering machines, using the “call back” functions and other useful features. Moreover, the quality of communication in most cases is not inferior to what is achieved on the most modern digital telephone lines.