The main feature of VoIP is that it combines both voice and data communication on a single network. Using this technology, voice and fax traffic are carried over an IP network with the help of common Internet equipment.



VoIP is a technology that allows users to make telephone calls over the Internet offering a multitude of advantages. The greatest feature is the ability to make local and more important global distance calls at a significant lower price than over a plain telephone.

VoIP came out originally as a technology that provides voice communication between computer users in different locations. It was new, daring and attractive. But it didn't stop at computers. As the industry of telecommunications developed, people started to use VoIP first in PC-to-phone connections and then, after a brief period of time, for phone-to-phone connections.

But how does VoIP work? It requires from both users (sender and receiver) a broadband connection meaning a high-speed Internet connection (cable/DSL modem). Broadband modems were initially used for connecting PCs to the Internet, but, after VoIP started to kick in, telephones were connected directly through these modems making possible the functionality of this new technology.

A VoIP call starts with the user's voice (analog) being sent from the regular phone to a device called Analog Telephone Adapter (ATA). This device converts the analog voice into digital samples with the help of a converter. The digital samples must be compressed into a standard format in order to be carried faster and more efficient. This process is done by digital signal processors which use codecs in order to shred the segment voice signal into frames. The compressed data must be put in IP packets. VoIP protocols use Real-Time Transport Protocol. Packets are transmitted over the Internet with a voice communication protocol such as SIP (Session Initiation Protocol). The CO (Central Office) is the final step where the decision to where the call must be sent is taken.

SIP is a protocol, more exact - a signaling protocol, and it is one of the main branches of the telecommunication industry. It is a request/response protocol for starting communications between two users and it has several features: the medium (text, voice), the transport (RTP) and the encoding (codec). Other related functions of SIP are the abilities to indicate call ending and instant messaging.

SIP has many advantages among which ?tech geeks? include: stability, speed, flexibility, security (encryption), authetification. The first line of a SIP message contains the type of message and the version of SIP chosen. In requests, this line has an address (SIP URL) which represents the destination of the message.

SIP is frequently used in the VoIP technology but also in videoconferencing, answering machines, networked games, cell phone games and mobile e-bussiness applications. Also, it is already common knowledge that Java offers excelent support for SIP.

A simple tool, SIP is chosen by many providers in order to build converged voice and offer multimedia services. Still, we have to bear in mind that SIP does not do conference control. It isn't a resource reservation protocol and it can never be linked with the quality of service.

VoIP and SIP are part of a new technology which allows phone-to-phone connections with the help of the Internet. While VoIP is already used by a lot of big companies in order to cut down on their expenses on business communications which include fax, conference calling and streaming video applications, SIP is just the protocol used for establishing sessions for an IP network.

SIP responds to the need for a catalytic protocol in the management of a VoIP call. SIP includes finding potential call participants and contacting them no matter where they are on the Globe or if they change their location. So, if you want to make a phone-to-phone conversation using the Internet, VoIP is just the thing for you. It has incredible extra features such as: video, conference, data exchange and, most importantly, it is cheap. Do not hesitate to choose this technology because it is a good option!