Introduction to telephony IP

Introduction to telephony IP

Systems of telephony

From the invention of the telephone by Alexander Graham Bell at the end of century XIX, the telephony systems have not changed substantially. It is necessary to recognize that the movable telephony has caused a revolution, nevertheless, for companies and offices the traditional one follows in operation.

Diverse improvements have been developed as the marking by tones DTMF and the identification of calls. Even so the basic functionality is the same.

At the end of noventas many investigators, as much oriented to educative aims as to commercial solutions, were interested seriously in transporting voice and video through public and private networks operating in protocol IP. Teconolgía developed for this aim is what now Telephony IP is known as and is, in simple terms, the process to fragment audio and the video in small packages, to transmit them by the network at issue and to defragment them during the reception in such a way that two people can communicate.


A commutator or PBX (Branch Exchange - by its abbreviations in English Prevails to you) is an equipment that gives service of local telephony to a company interconnecting called between users of the same using local lines and sharing external telephone lines.

A commutator provides with functions nonavailable in traditional telephone lines PSTN (Public Switched Telephone Network - by its abbreviations in English), among them: voice mail, multiconfers and one of most interesting: the interactive system of answer by voice or IVR (Interactive Voice Response - by its abbreviations in English)

Traditional commutators

The traditional commutators integrate external the analogical and digital lines (main) and provide lines (extensions) of characteristics similar to the users of the company. These commutators are seen severely limited in the amount of main and extensions that can usually support and, those that have the best capacities of exptansión, are very expensive. A typical problem appears for the service of IVR, that usually is not available for all the main simultaneously, when several simultaneous calls are received, some will be taken care of and others will have to hope.

Another important characteristic of the traditional commutators is that they require of a dedicated cable to interconnect it to a particular extension.

These commutators support practically any type of conventional and digital telephone, as well as FAX.

Commutators IP

Integrated mainly in equipment dedicated or based on computers and/or servants standard, they integrate all the functions of the traditional commutators and add a great amount of others more.

In the same way that the traditional ones use special cards to connect the main ones. Our commutators IP support main cards for analogical of up to four lines each, main expandibles cards from four to 24 analogical ones and cards for main digitalises by connections E1/T1.

Commutators IP do not require of specialized ports to connect extensions of voice over ip, nevertheless, modems or FAX can be provided for special cases as service for. The extensions “are connected? to the commutator by means of the data network of the company, as any personal computer.

Taking into account the previous thing, the amount of extensions that can support is limited by the capacity of processing of the commutator and the speed of the data network. Our simpler commutators IP support at least 80 extensions.

The means by which the commutator with its extensions communicates can be the structured wiring traditional, fibre optics, connect wireless, VPNs of low speed, connect DSL or of cable.

Between the added value functions that our commutators offer they are: recording of calls; pricing schemes; simple configuration; they count on the capacity to execute programs developed especially for automatic services, for example, consultations of balance via telephone; shipment of the messages of by email electronic mail of voice; interconnection of branches by connections of Internet dedicated and/or simple as lines DSL saving the cost of calls of long distance; Simultaneous IVR in all the main and many more


The telephones allow us to connect to us to the lines of the public system and to the commutators directly to realise calls.

Conventional telephones

They can be analogical or digital. First they are of common use and they are connected to the public system or to analogical ports of the traditional commutators, they offer the well-known functions of call and some include a screen that can unfold the number of which a call or a list of lost calls is being received.

The digitalises offer some additional functions as indication of llamdas in process or entrants and bellboys of direct access to these main calls or of entrance. Some even support systems of simple text mail.

Telephones IP

A telephone IP is in escencia a computer. Of a very specific use clearly, but in himself a computer. The majority of all is formed from their own keyboard or a website integrated in them.

By his characteristics they only can operate in data networks. By their direction IP without needing a commutator have the facility to communicate among them and some models even support video confers. They provide with all the functions that analogical and the digital ones offer and even models with support for WiFi exist.