What Is Digital Voice Phone Service?

By Rebecca Mecomber

Some routers have VoIP adapters built in.
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Telephony has evolved since Alexander Graham Bell's acclaimed cry, "Watson, come here. I want to see you," in 1876. For over 100 years, the traditional method of telephone service has consisted of analog sound waves transmitting across copper wires strung from telephone to central switchboard to telephone. Digital phone service, commonly called Voice over Internet Protocol, or VoIP, is telephone service transmitted over the Internet. VoIP features many benefits over traditional telephone networks, but it has a few disadvantages as well.


The concept of digital phone service developed with the advent of high-speed broadband Internet service, but progress was initially slow as a result of the scarcity of broadband service. In 1995, Israeli company Vocaltec introduced the first VoIP software for computer-to-computer connections. Five years later, only 3 percent of telephone calls were made using VoIP technology. As broadband Internet service became available and as technology afforded better equipment to produce clearer audio, VoIP has become a increasingly essential commodity, especially for businesses.


Voice over Internet Protocol digitizes analog voice data into Internet capable TCP/IP data packets. The data packets are routed to a call handler, or VoIP server, maintained by a VoIP service provider. Special VoIP equipment, such as an IP phone or telephone adapter that converts digital data to analog data, transmits and distributes audio data to the listener. Some Internet service providers (ISPs) combine VoIP service with their high-speed Internet service, while other companies, such as Skype and Vonage, charge customers for the use of their VoIP servers.


Advantages abound, which explains why demand for VoIP service is soaring. VoIP offers the same high quality audio for a fraction of the cost of traditional telephone service. Because data and voice transmissions use the same digital network, VoIP users experience reduced infrastructure costs and unlimited long-distance calling. VoIP incorporates special features such as caller ID, conference calling and combined voice and data transmissions for no charge compared to the expensive traditional phone service features. Specialized VoIP transmissions allow encryption of calls to provide secure data transmission when necessary.


When first developed, quality of sound and latency issues hindered clear VoIP transmissions. Improved VoIP devices have solved the problem, although older or inferior VoIP devices may still experience transmission difficulty. VoIP requires special VoIP phone equipment and an active, broadband Internet connection. In the case of a power outage, VoIP telephone service is lost, unlike traditional telephone service, which continues operating because it does not rely on the power supply system. As with all digital data transmissions, unsecured VoIP data can be intercepted or the equipment hacked.