الجمعة، 25 مارس، 2011

الاتصال المجانى عبر الانترنت حقيقة مش كزب


VOIP solution: voice over ip phone services providers
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Voice over Internet Protocol (VoIP, IPA) is a general term for a family of transmission technologies for delivery of voice communications over the Internet or other packet-switched networks. Other terms frequently encountered and synonymous with VoIP are IP telephony and Internet telephony, as well as voice over broadband, broadband telephony, and broadband phone, when the network connectivity is available over broadband Internet access.


Voice over Internet Protocol (VoIP, IPA) is a general term for a family of transmission technologies for delivery of voice communications over the Internet or other packet-switched networks. Other terms frequently encountered and synonymous with VoIP are IP telephony and Internet telephony, as well as voice over broadband, broadband telephony, and broadband phone, when the network connectivity is available over broadband Internet access.

VoIP systems usually interface with the traditional public switched telephone network (PSTN) to allow for transparent phone communications worldwide[1].

VoIP can be a benefit for reducing communication and infrastructure costs by routing phone calls over existing data networks and avoiding duplicate network systems. Skype and Vonage are notable service provider examples that have achieved widespread user and customer acceptance and market penetration. Other providers are also available. See List of commercial voice over IP network providers.

Voice-over-IP systems carry telephony speech as digital audio, typically reduced in data rate using speech data compression techniques, packetized in small units of typically tens of milliseconds of speech, and encapsulated in a packet stream over IP.

Can I call using the internet connection?
After its introduction, Internet telephony has been highly developed rapidly in a brief period. Many software developers currently offer PC telephony software. However, more importantly, gateway servers are rising to act as an interface between the Internet and the PSTN (It expands as Public Switched Telephone Network). With voice-processing cards, these gateway servers allow Internet telephony VoIP(It expands as Voice Over Internet protocol) users to communicate through traditional telephones over long distances without exceeding "Long Distance" telephone network.

A telephone call travels from the local PSTN to the nearest gateway server, which digitizes the traditional, analog voice signal, converts it into IP packets, and moves it to the Internet for transport to a gateway server at the receiving end. This server alters the digital IP signal back to analog and concludes the call locally. With its Internet telephony support for computer-to-telephone calls, telephone-to-computer calls and telephone-to-telephone calls, Internet telephony VoIP represents a vital step toward the merging of voice and data networks.
The History and Advances made in Internet Technology
Voice ove r Internet Protocol (VoIP) is becoming a substitute to traditional telephone service. The goal of VoIP Deployment is to receive the registered location information of a VoIP user to the most suitable public safety answering point (PSAP) through statewide standards using the 9-1-1 network.

Most VSPs will perform with a database provider known as a Voice Positioning Center (VPC) and have access to 9-1-1 network through an Emergency Services Gateway (ESGW). VPCs are utilized to update and store registered user location information. . It then imparts the details to PSAPs when a 9-1-1 call is rendered. ESGWs are those Competitive Local Exchange Carriers (CLECs) that supply the connection interface into 9-1-1 network.

Initially regarded as just a novelty, Internet telephony is attracting a number of users due to the fact that it offers remarkable cost savings relative to the PSTN. Internet telephony service users can sidestep long-distance telephone carriers and their per-minute usage rates as they run their voice traffic over the Internet for a simple, flat monthly Internet-access fee. VoIP Internet telephony provides a viable threat to the providers of long-established telephone services that should stimulate enhancements in function and cost throughout the industry.

On top of the game are Gizmo Project and Skype which rely on a software client on the PC to place a call over the network. This is where one user ID can be used on different computers or in different locations on a laptop. In the middle are VoIP Internet telephony services like Vonage or BroadVoice which also provide a telephone adapter for connecting to the broadband connection similar to Internet telephony services offered by broadband providers, but which are targeted towards sophisticated users and enables portability from one location to the next.
Challenges of Internet Telephone Systems
VoIP Internet telephony refers to communication systems services- whether it's the voice, fax or voice-messaging applications that are conveyed via the Internet, rather than public switched telephone network (PSTN). The basic steps involved in originating an Internet telephony service telephone call are conversion of the analog voice signal to digital format and compression or translation of the signal into Internet protocol (IP) packets for transmission over the Internet. With the Internet telephony service, the process is then reversed at the receiving end.

Internet telephony VoIP technology still has a few limitations that have stirred some to believe that it is not prepared for ubiquitous deployment. However, many industry analysts anticipated that 2005 was the "Year of Inflection". This is when more IP PBX ports were shipped than traditional digital PBX ports. Therefore even though there are limitations it is no doubt advantegous and helps to a gret extent.

One drawback is the failure to forward faxes due to software and networking restrictions. Another stumbling block is the failure to make telephone calls w hen the power supply is inadequate.. Re-wiring is necessary to use the telephone jacks in the typical house. If VoIP is used in solitary LAN (with no internet connection), then it would utilize resources akin to a PABX.

Variation in delay is often referred to as jitter. The effects of jitter can be moderated by amassing voice packets in a play-out buffer upon appearance, before playing them out. This evades a condition known as "buffer under run", in which the play-out process runs out of voice data to play due to the next voice packet which is yet to arrive, but enhances delay by the span of the buffer.

Tutorials discuss the ongoing brisk evolution of VoIP Internet telephony. The market forces invigorating the evolution and the benefits that Internet users can realize.. It also examines the obstacles that must be cleared before VoIP Internet telephony can be adopted on a pervasive basis. This is a service enjoyed by many.