Voice-Over-IP

From Isopedia

1 Technical Information
2 History
3 Citations
4 Team Members

Technical Information

Voice over Internet Protocol (VoIP) is when a telephone call travels accross an internet protocol (IP). So, instead of plugging a phone into a regular PSTN phone connection, the user plugs it into an internet connection. VoIP has many advantageous properties that a regular phone connection lacks.

The DSL or Cable modem plugs directly into the VoIP adapter, which then routes the internet connection to all of the devices plugged into the adapter. The devices are usually phones and a Local Area Network or LAN. A LAN connects all of the PCs, laptops, and other networked devices in a business.

In order for a VoIP Connection to work, an Analog to Digital Converter (ADC) must be used in order to change analog voice signals to digital signals. First the format of the bits are modified by the ADC in order to make the transfer easier. Next the voice packets are put into into data packets using a real time protocol over IP. The receiver of the call is then called using a "signaling protocol" called ITU-T H323. Once the receiver's phone or computer has gotten the data it is converted back into an analog format. The data is then directed towards the receiver's sound card or phone. Once this occurs the receiver can now here what the sender said. The minimum requirements for a VoIP system are a PC 386, sound card that is full duplex capable (so the user can hear while he or she speaks), and a network card or connection to the internet that allows communication between two PCs.

Voice over IP technology has more capabilities then regular telephone services. These capabilities include the ability to take calls from anywhere in the world as long as the user's VoIP phone is connected to the internet. This is very useful to people who go on business trips. For example, if a user has a Fairfield, CT phone number and that user travels to Asia and someone calls the number it will still ring in Asia. Also, if a call is made from Asia to Fairfield, it is treated as a local call, even though the caller is currently in Asia. This mobility is one of VoIP's greatest assets. Another benefit is users can use the VoIP phone anywhere in the world as the long as they have a fast and stable connection to the internet. One of the best advantages is the fact that VoIP providers usually include call fowarding, 3-way calling, and automatic redial as a free part of their plans. For most current telephone companies, a person has to pay a fee to get these options.

History

Voice-Over-Internet Protocol or VoIP as it is abbreviated was introduced originally during the 1990’s as an alternative to traditional long-distance calling. The first VoIP application was from an Israeli Company called VocalTec; they released their product into the market in 1995. Unfortunately, VocalTec was plagued with many problems, such as disconnects, incompatibility issues, low voice quality, and delays due to congestion and slow connect speeds. Back in the 90’s VoIP was barely worth-while and as a result the new technology struggled. As the years progressed, however, the technology improved. By 1998, small companies had developed PC to phone connections through Voice over IP. Soon after this came phone to phone connections using VoIP. Around the year 2000, Voice-Over-IP made tremendous strides when technology companies like Cisco Systems and Nortel Networks developed equipment capable of switching, meaning that the PSTN can read the voice data packet and vice-versa. This technology allowed for the removal of PC’s from the equation, as they became no longer necessary. People could use special phones instead of computers, which was much more practical. This technology gradually became more and more affordable, drawing newer, larger companies into the mix, making VoIP even more well-known. Eventually long distance providers were drawn to VoIP, these companies were the original target market of VoIP products. The long distance companies began using VoIP to route long distance network calls over the internet to help reduce costs. Today VoIP has been popularized thorough companies like Vonage which produces broadband phones with cell-phone like calling plans at discounted rates. Recently released was Skype, a free downloadable copy of VoIP software, which allows users to call any other Skype user anywhere in the world for free. It is expected that there will be nearly 5,000,000 US households which use VoIP products to communicate according to the Forrester Research Group (September 2002). The Juniper Research Group in January of 2006 estimated that this number would more than double by years end 2009, rising to nearly 12,100,000 US households. In the future it is expected that Voice-over-IP enabled cell phones will allow users to connect wirelessly over Wi-Fi Networks linked to cell networks. As users pass from the cell network into the range of a wireless network, the phone will automatically switch the call to the wireless network. It was a difficult start for VoIP; however, the technology is currently growing and appears to be here to stay.