Yes! Internet telephony puts the power to make voice calls using the Internet in your hands. IP (Internet Protocol) telephony involves the transfer of your voice to the other person's computer or telephone using the Internet as the transport medium, rather than the conventional wired telephone system. All you need is a multimedia computer and access to the Internet. The software usually comes free and enables you to make voice calls over the Net… free (well, almost) and pronto!

Get Your Voice Over

The whole concept is based on the utilization of Voice over IP or VoIP, which has been around for almost half a decade now. VoIP makes it possible for the Internet to carry voice signals like any other data that is transmitted through this network.

Since the normal voice signal is too large to transmit after it is digitized, data compression algorithms-similar to those used to compress audio files to MP3s-are used. This has to be done because bandwidth-the capacity to transmit and receive data-is always in short supply on the Internet. This hugely cuts down on the quality as well as the quantity of the signal to be transmitted, and hence makes it possible for them to be moved around on the Internet. Codecs (coders/decoders), embedded into the software, are used to encode these audio signals into digital data and decode them into voice at the receiving end.

Like any other network, the Internet functions by following a commonly agreed protocol for its functions. A protocol is a set of rules designed to tell computers how to do things in different situations arising in the normal course of the network's working. The Internet largely uses the Internet Protocol (IP) to transmit data. Therefore, Internet telephony is also referred to as IP telephony.

Essentially, IP cuts the data to be transmitted into data packets and tells each one of them the receiver's address. All the packets then reach the receiving end and get assembled into a single piece again. The packets are the means and the end to everything here. Also, there are gateways in the way, which are used to provide conversions from traditional telephony to Internet telephony and vice versa. Thus, when you call up a fixed phone from your PC, they connect from the Net to the traditional phone network and complete your call.

The normal telephone connections, on the other hand, transmit those voluminous voice signals as voice only, and hence, require a physical connection from the caller to the receiver for the duration of the call.

This is where those long, endless lengths of cable laid around the globe by telephone companies come into the picture.

Say hello to Threedom

There are three types of phonecalls that you can make using the Internet. The first kind is the PC-to-PC call, where both parties have to be online while the call is made. PC-to-phone calls allow you to make phonecalls to any other phone in the world using your PC. The third kind of calls are phone-to-phone calls and are not commonly used currently due to their complex nature. So, we'll leave them out for now.

Ring Requirements

To make any kind of phonecalls using your PC, you need a computer which is fitted with a full duplex sound card. Check your sound cards because the keyword here is 'full duplex', which allows you to speak and listen at the same time. If you have a half-duplex sound card, you will be able to either speak or listen, but not do both at the same time. Along with it, you need a microphone and speakers or headphones attached. Plus, of course, you need a modem and a connection to the Internet.

For PC-to-PC calls, you need to install some software like Media Ring Talk or Microsoft Net Meeting, and make sure the person you want to call also has the same software installed. These days, instant messengers like Yahoo!, MSN and ICQ also come with capabilities to talk, using their software. Then, when both of you are online, you can talk or instant message at your own sweet will. These services are usually free.

PC-to-phone, too, is as good as free. The Web is scattered with banner advertisements shouting 7.9 cents per minute to any part of the world. This gives you rates as low as four rupees or less compared to the 200 bucks for a three-minute call to the US. But for this, you'll need an international credit card as well, since these call cards are sold in dollars as of now.

The Good & The Bad

Internet telephony doesn't require you to have a physical connection at any time of the call. The conventional phone networks charge your long distance calls depending on the distance and duration. Thus, all those various charges shared between the various telecom operators are totally bypassed while making Internet calls. This drastically cuts down the costs, and that is why VoIP calls come as cheap as they do.

Another advantage is the full utilization of bandwidth. When you make a normal phonecall, you allocate a bandwidth that only the two parties talking can use between themselves. Here, there is no such allocation, and this hugely improves bandwidth utilization. This saves a lot of precious bandwidth, which means a lot on the Internet.

Despite rapid advancements, Internet telephony still has limitations. The quality of sound transmitted remains poor for the moment, because of the not yet perfect technology. Another problem is the delay factor, also called Latency. The packets are sent using the shortest route possible, and hence at the time of reassembling, some packets might be lost or may arrive late. This happens due to congestion on the route of the packet. This creates jitters and echoes in the voice, which are heard at the other end and might create confusion for the listener. Most of the time, though, the sound quality is acceptable even on the slower dial-up connections. But for the cost factor, which is less by a major magnitude as compared with the conventional phone, it's a small compromise.

Internet telephony is just one of the marvels of technology that have come along in the small lifetime of the Internet. And it is just one of the long list of applications meant to make the 'connecting people' mantra of the Net come true.

Down Legal Street

A word of caution before you actually make that call. For the moment, the Indian Rule Book states, 'Telephony on the Internet is not permitted.' So, legally you can't take advantage of Net telephony in India. This is to help our telecom carriers earn their money as long as they can from us janta. But this has not stopped many a cyber café owner from offering cheap calls to your pals in the US or elsewhere. Of late, things have changed for the better and there are indications that Internet telephony will be legalized in early 2001. So, cross your fingers and wait for a decision to come.