VoIP: Talking Over the Internet


This article was published by ComputorEdge, issue #2701, 2009-01-02, as the cover article, in both their PDF edition (on pages 6-8) and their website.

As the ultimate computer network, the Internet serves as a platform for the global distribution of digital data — including Web pages, images, text files, executable programs, e-mail messages, and audio clips. That last category comprises a variety of components, varying in size, purpose, and format — such as a one-second user feedback beep attached to a Web page element, a one-hour webcast focusing on financial news, or a two-hour live blues concert delivered to online listeners as streaming audio.

The ability to communicate digitized sound over the Internet, regardless of its content, suggests the possibility and potential of digitizing and transmitting phone calls, in real-time, over the Net. It turns out that it is quite feasible. After all, if something can be digitized, then it can be transmitted over the Internet — including any kind of audio content. This is made possible by Internet Protocol (IP), which specifies a method of communicating data over a network, by organizing it into small chunks, referred to as packets. IP is what makes the Internet so robust, as it automatically directs this network traffic along the most efficient pathways.

Packet voice technology can trace its roots to 1993, starting with the efforts of Lior Haramaty and Alon Cohen, members of the Israel Defense Force at the time, and later founders of VocalTec Communications. Yet it did not really take off in the United States until the early 2000s, with the widespread penetration of broadband Internet access throughout the country. This is primarily due to packet voice technology not working well over dial-up Internet connections, since the voice signals, when digitized, become huge amounts of binary data that can only be handled by broadband Internet (DSL, cable, or satellite).

Talk Globally, Call Locally

This method of communication is known as VoIP, which is short for "voice over IP". Yet not all such Internet telephony is created equal. In one form of Internet telephony, the customer talks using his regular phone, connected to a VoIP adapter, which digitizes the outgoing sound and sends it over the Internet using his high-speed Internet connection. The customer does not require local phone service to make the call. His voice signal is sent by the particular VoIP company to one of their servers — known as a VoIP gateway — located in the calling area of the listener. That signal is converted back to analog sound, which the recipient hears using her own regular phone, as a local phone call, regardless of what country the caller is located in.

An example of this approach, is Vonage (pronounced VON-uj), which bills itself as a leading provider of VoIP internet broadband telephone services. As of this writing, subscribers can make unlimited local and long-distance calls for less than $25 per month. This price does not include all of the "regulatory and activation fees and certain other charges, equipment taxes", etc., which certainly add up, month after month. These extra costs are similar to those of traditional long-distance phone services, which many VoIP subscribers abandoned precisely in order to get away from all of those tacked-on fees. Nonetheless, Vonage has plenty of customers; a chart on the company's website indicates that, from 2003 to 2008, they have gone from zero to 2.5 million subscribers.

Another approach is to do away with the use of regular telephones, and instead transmit the digitized audio back and forth between computers on both ends of the conversation. The most popular example of this type of Internet telephony, is Skype, which offers a range of features and plans — some free and others paid. There is no cost for two users to send voice, video, and instant messaging back and forth, with both participants running the Skype program on their PCs. Even conference calls of 25 or fewer people, are completely free.

But most people do not have Skype running on their computers, and some people do not even have personal computers or Internet service. So how can one call, using Skype, such an individual? Fortunately, Skype makes possible local and international calls to regular phones, in which the sender's voice signal is sent over the Internet to the recipient's area, where it is turned into a local phone call — similar to Vonage's service. At this time, three different monthly plans are available, and all of them are far less expensive than conventional long-distance service for an average caller. Unlimited calls within the United States and Canada cost $2.95 per month; $5.95 within Mexico; $9.95 for unlimited global calling. For people who make a few phone calls per month, Skype's pay-as-you-go plan would be a better choice, since calls cost only 2.1 cents per minute in 35 major countries; other countries cost more.

On the Phone, on Your Computer

Computer-based VoIP, such as Skype, is especially convenient. It is performed by a given VoIP application, running on the personal computers of everyone involved in the conversation (including uninvited participants — usually members of US federal government agencies sporting three-letter acronyms). On the PC of the person speaking, the VoIP program digitizes that caller's vocal sounds in real-time, organizes them into the digital packets required by IP, and sends those packets over the Internet to the listener's computer. The VoIP program running on the recipient's computer, reassembles all of the received packets into audio, which the listener then hears.

In terms of the hardware required for VoIP communications, any handheld or headset microphone would be adequate for sending one's voice. Commercial VoIP services typically make available — and often even require the use of — specialized handsets. At the other end, the listener can use any stand-alone or headset speaker(s) that can be connected to the sound card of her PC, or the audio output of her PC's motherboard.

Voice quality, as perceived by the listener, is affected by many factors, including the quality of the sender's microphone, how well positioned it is in relation to his mouth, the upload speed of his Internet connection (the greater the speed, the less delay for the recipient in receiving his voice signal), the frequency of dropped or delayed packets (the higher the frequency, the worse the voice quality), the download speed of the listener's Internet connection, the quality of her speakers, and background noises in their respective environments. These are most if not all of the possible technical factors, and do not include the human factors, such as how well the speaker articulates his words, how fast he talks, and the strength of her hearing abilities.

Pluses and Minuses

For those people who have been using VoIP for some time now (myself included), the advantages are obvious. The potential savings are quite attractive, proportional to how much non-local (outside your zone) and long-distance phone calling one typically makes. In fact, with the unlimited calling plans, you may find yourself making far more calls, and longer ones, than ever before — thus enjoying conversations with family members and friends even more, without worrying about mounting long-distance plan costs. Not only can you slash your per-minute costs, but by not committing to a long-distance provider, you avoid all of their monthly fees, including those charged even if you don't make a single phone call that month.

In addition to reducing your telephony costs, VoIP opens up a host of communication possibilities that Graham Bell could only have imagined. As noted earlier, Skype allows you to send video as well as audio, back and forth. That is certainly not a feature offered by conventional local and long-distance phone services.

Yet as with any new technology, there are some downsides to VoIP. Even though voice quality continues to improve, it is generally not equal to that of landlines — especially for free VoIP services. On the other hand, it is usually as good as the voice quality of cell phones, with far fewer rates of disconnected calls.

Another area of potential problems is that of emergency and technical support calls. For example, some VoIP services do not support 911 calls. Those that do, such as Vonage, require the customer to disclose their physical address, which is (understandably) required by emergency services. Another example is VoIP's reliance upon Internet connectivity. In other words, if you lose your broadband connection to the Internet, how do you call your Internet service provider (ISP) to report the problem? This naturally is not an issue if you have a cell phone, or someone in your household does (check your teenager's room).

But on balance, the advantages of VoIP far outweigh the disadvantages, and it is little wonder that more and more people are opting for Internet telephony, and abandoning the long-distance services that used to have a stranglehold on our communicating with people across the country and across the oceans of the world.

Copyright © 2008 Michael J. Ross. All rights reserved.