Internet telephony refers to routing voice telephone calls over an Internet Protocol, or IP, network. This section explains a little about how Internet telephony works. If all you want to do is learn how to use Internet telephony, you can skip ahead in this chapter to the sections that tell you where to sign up for the service, how much it will cost, and what additional hardware you may need.
Although a private network is involved in some cases, for the most part, phone calls are routed over the Internet. This is achieved using a combination of hardware and software.
Another term for Internet telephony, which I will be using in this chapter, is VoIP, short for Voice over IP.
Although the quality of VoIP may not be quite up to that of plain, old-fashioned telephonics, the quality is quickly getter better, and this has become less of a concern. In fact, most voice telephone calls you place today will in part be routed using VoIP, even if they start out (and end up) as regular voice telephone calls.
This brings up the point that VoIP comes into play a lot of ways in today's telephonics. For example, even if a phone call starts out being placed with a conventional "last mile" provider over old-fashioned phone line and received in an analogous fashion using a regular telephone, it is likely that the "long haul" portion of the phone call was routed using VoIPsimply because it is a less expensive way to manage telephonics than an old-fashioned dedicated network.
A more end-to-end VoIP solution is just starting to be offered by upstart telecommunication companies such as Vonage, http://www.vonage.com. Provided that you have a broadband Internet connection, Vonage proposes to replace your existing conventional phone system with VoIP-based telephones, which are both cheaper, easier to configure, and with more featuressuch as free multiline voice mail, call blocking, call forwarding, and more: all configurable telephonically or on the Web.
Pulver Innovations (http://www.pulverinnovations.com) makes a standalone Wi-Fi telephone that uses VoIP when it is in range of an open wireless broadcast signal (or one to which it can log on). There have been reports that Vonage is testing this phone for use with its VoIP service.
Skype offers VoIP service free anywhere in the world between computers that run Skype software. An extra-charge service called SkypeOut enables a PC to make calls to conventional phone numbers and another service called SkypeIn enables a caller on a conventional phone to call your PC. All these capabilities and more are described on the Skype website at http://www.skype.com.
Some companies are also introducing dual-mode cell and VoIP Wi-Fi phones. These use a cell network when Wi-Fi is unavailable and take advantage of the lower cost of VoIP over Wi-Fi when they can.
You can pretty easily turn your laptop that uses Intel Centrino mobile technology into a VoIP, Wi-Fi monster. Once you have done this, you can use your mobile computer to call other VoIP computers, or to call regular, old telephones as shown in Figure 6.1
Figure 6.1. Calls are placed over the Internet from a computer using VoIP to another computer or a regular phone.
Although carrying around a mobile computer that is also a telephone is bulkier than just carrying around a cell phoneis that a cell phone in your pocket, or are you just glad to see methere are some real benefits to adding VoIP to your laptop. These include