VoIP - using the Internet as a telephone service

For many Internet users there's a new techie buzzword doing the rounds and if we believe everything we hear, it is going to be huge. It’s all about Internet telephony, sometimes called VoIP or Voice over Internet Protocol – which is about making telephone calls using your Internet connection.

Traditionally the underlying technology of the Internet Protocol (IP) has all been about getting any two online computers to firstly find one another and then exchange information – which has been pretty much the basis for the entire Internet so far.

However, as of right now the Internet can also link callers in a live, two-way spoken conversation. Perhaps more importantly, seeing as you are already paying for your Internet connection, many of these calls can be considered effectively free.

So if the Internet has been all about connecting computers, how does it work as a telephone system?

When you make a call with a system that uses an Internet telephony service, the sound of your voice is broken up into a highly compressed digital stream of separate data 'packets' and transmitted through your Internet connection. When the “packet” gets to the other end, they are turned back into sound and when it works, as it should, it’s a very nice system.

Having said that however, Internet telephony still remains an imperfect technology. While compression reduces the amount of data transferred during a call it can also affect audio quality. The designer needs to strike a balance between compression, quality and available bandwidth. What this really means is that a phone call over the Web will always be best made over a broadband Internet connection.

What happens if you do get a poor connection?

A poor connection over the web usually results in slow-to-arrive data packets which can cause the stutter-like effect characteristic of web calls where words occasionally get cut in half or syllables disappear completely. The problem is made even worse when callers talk over one another during the conversation.

Internet phone calls can also be susceptible to interference. Only when it's possible to guarantee either end of the connection and most of what lies between, is it possible to guarantee quality of the call.

So using an Internet phone system is the same as an ordinary phone system – just pick up the handset, dial the number and off you go?

Err, no, not necessarily. There are basically three different types of Internet telephone systems – each have their own benefits and drawbacks.

At the simplest level, you can use your computer to “call” another computer at the other end. For this system to work both parties must be online at the same time and using the same kind of software, but calls are essentially free, so you can talk to someone on the other side of the world without really having a time limit or incurring the national debt.

The next type is a type PC-to-telephone system. You can make outgoing calls from your computer to normal telephone numbers (if they are available). This form of call will usually save you a lot of money in long distance calls as well.

Lastly, there is an all-new breed of Internet phone system where you make and receive calls on a standard telephone handset. These calls are routed out over a broadband Internet connection rather than the telephone network. You can in some instances even get a new phone number as part of the deal.

There are a couple of other factors to take on board too. At present, international calls are restricted to about only seventeen countries, although we are assured that this coverage will expand. You can call mobile phones but not premium-rate numbers.

Just what exactly is required to make calls across the ‘Net?

Hardware requirements will vary according to the type of Internet telephone system you intend to use. Of course for PC-to-PC or PC-to-phone calls, you must have at least a computer.

Obviously you will want to be heard, so you will need to connect a microphone to the appropriate socket on your soundcard. On the other hand so you can listen to your callers, you can choose to either use the computer's speakers or, better still, invest in a pair of headphones. Any good web call software should assist in the installation and setup. A good choice is a headset with a built-in microphone, they are usually better and more convenient than a separate mic-on-a-stick setup.

Any tips for getting the best out of an Internet phone connection?

Well, here are a few, although each user tends to evolve their own style. Try using headphones, rather than speakers. This will usually prevent feedback at your end of the call and an echo occurring at the other.

During a call it is usually not a good idea to be doing file transfers, downloading email and in some cases, even surfing on the Web. They can all have a very detrimental effect on the quality of the call by overloading the connection.

Protect your privacy. Never provide details in a profile that is placed on an Internet “directory” that could personally identify you. Unsolicited phone calls are an invasion and can become a nuisance. Setup your system so that you only accept calls from known or acceptable callers.

When making a call, try to make sure that you take turns at speaking. You'll get a much better result this way.

What about video conferencing is that the same thing?

For many, sending live video pictures via a webcam is a natural progression to making voice calls over the Internet. With the correct setup this is perfectly possible and has been for quite some time. For the best results a broadband connection will provide the best performance. Even so, currently for showing grandma the kids, it's fine, but for most the quality remains an unacceptable level of performance for business quality video conferencing.

Arthur Hissey
Computer Research & Technology
www.crt.net.au