VoIP - Voice over Internet Protocol

Woman with headset
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VoIP (Voice over IP) technology allows telephone calls to be made over computer networks like the Internet. VoIP converts analog voice signals into digital data packets and supports real-time, two-way transmission of conversations using Internet Protocol (IP).

How is VoIP Better than Traditional Phone Calling

VoIP offers a substantial cost savings over traditional long distance telephone calls. The main disadvantage of VoIP is a greater potential for dropped calls and degraded voice quality when the underlying network links are under heavy load.

How Do I Set Up VoIP Service?

VoIP calls are made on the Internet using VoIP services and applications including Skype, Vonage, and many others. These services run on computers, tablets and phones. Receiving calls from these services requires only a subscription along with a standard audio headset for speakers and microphone. Alternatively, some service providers support VoIP through ordinary telephones that use special adapters to connect to a home computer network, sometimes called broadband phones.

Costs of a VoIP subscription vary but often are less than for traditional residential phone service. Actual costs depend on the calling features and service plans chosen. Those who get VoIP service from the same company that provides their broadband Internet service typically get the best deals.

What Kind of Internet Service Is Needed for VoIP?

VoIP service providers offer their solutions over most kinds of broadband Internet.

A typical VoIP call only requires about 100 Kbps for best quality. Network latency obviously must be kept low; VoIP over satellite Internet can be problematic, for example.

Is VoIP Service Reliable?

Old analog phone service was incredibly reliable - sound quality was predicatable and even if a home suffered a power cut, the phones usually continued to work as they were connected to other power mains.

In comparison to that, VoIP service is less reliable. VoIP phones fail when there is a power outage at the residence and sound quality suffers sometimes due to network contention. Some people install a Universal Power Supply (UPS) battery backup system for their home network, which can help. Network reliability also varies with the VoIP service provider; many VoIP implementations are based on the H.323 technology standard.

Is VoIP Service Secure?

Traditional phone lines can be wiretapped, but this requires physical access and installation effort. VoIP communications, on the other hand, can be snooped over the Internet electronically. Likewise, network attackers can disrupt your calls by interfering with the flow of data packets. Ensure home network security systems are in place to minimize security concerns with VoIP.

How Good Is the Sound Fidelity of VoIP Service?

When the network is functioning well, VoIP sound quality is excellent. So good, in fact, that some VoIP service providers actually inject special sounds (called "comfort noise") into the transmission, so that callers don't mistakenly think the connection is dead.

Does Subscribing to VoIP Service Require Changing Phone Numbers?


VoIP supports phone number portability. Those switching from ordinary telephone service to VoIP service, can normally keep their same number. Note, however, that VoIP providers are normally not the ones responsible for switching your old phone number over to their service. Check with your local phone company as some may not support a number transfer.

Are Emergency Numbers Accessible With VoIP Service?

Yes. Emergency services (like 911 in the USA, 112 for the European Union, etc.) should be supported by any major VoIP service provider.

For more details about VoIP, see Voice over IP at About.com.

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