So, why hasn’t VoIP been a buzzword until recently? The answer is, for the most part, down to users’ Internet connections. IP doesn’t guarantee the order of data packets traversing a network, so they won’t always arrive at a destination in the same order as they were received (in fact, the packets might not all take the same route across the network. If a VoIP device or application were to presume the packets were in order, a conversation between two people could sound strange, or worse, be unintelligible. So, the packets of data must be reordered once received. However, if the packets of data have taken a long time to get to their destination, by the time enough have been received to restructure and play back, there will be a disconcerting time delay in the conversation, much like the delay you will have seen on television where an interview is taking place over a satellite link. Now that many users have higher bandwidth, lower latency Internet connections, VoIP technology is more feasible for widespread use.

If VoIP is to replace the Public Switched Telephone Network (PSTN) then it needs protocols in place that allow it to be as functional and useable. An increasing number of VoIP implementations utilize the Session Initiation Protocol (SIP), a protocol designed around the vision that audio, video and all forms of communication will eventually take place over IP based networks like the Internet. This allows features such as dialing numbers, ringing phones and hearing error tones, allowing for a familiarity in the transition from PTSN to VoIP, should it ever happen.

So, VoIP could eventually replace our existing global telephone networks, but why should it? What are the advantages of VoIP?

The big advantage we’re likely to see is cost. Routing a call between two or more phone companies to allow somebody in the UK to call Japan isn’t all that cheap. However, you’re not charged extra for downloading data from a website hosted in Japan. In theory, then, a VoIP call to Japan should be much cheaper than a traditional telephone call.

Changes to traditional telephone networks take place very slowly. The International Telecommunications Union, which regulated telecommunications globally, has to keep the telephone network standardized. However, VoIP services can innovate without restriction, which means rapid deployment of new features.

Yes, that means VoIP has more features than a traditional telephone. For example, as long as you have an Internet connection, regardless of where you are, somebody will be able to call you over VoIP. Take CallerID to the next level and you can transmit everything from address details to data files, sharing important information while you talk, which is a feature businesses will be keen to exploit.

VoIP isn’t without its drawbacks
First, there’s the competition, the mobile phone. The mobile is so popular that some people are ditching their landline, no longer needing it. A VoIP solution will only work when there’s a network connection. Even when you consider wireless connections, a mobile phone will have significantly greater coverage and therefore usability. Given their dominant position, mobile phones are expected to incorporate VoIP technology, rather than be pushed aside by it. This is quite feasible given the increasing features of modern phones, 3G and beyond.

Another problem is reliability. Land lines are not powered by the domestic electricity supply. If there’s a power cut, you should be able to use your land line still. If you’re running a VoIP system and there’s a power cut, chances are you’ll have no service… your modem/router just lost power.

Emergency calls are a problem too. Ignoring the problem of power cuts, dealing with VoIP based emergency calls can be difficult as it’s not always possible to locate the person or even determine the area they’re in and allow the call to be routed to a call center, which might have local knowledge. Mobile phone companies implemented a system to overcome this, but VoIP services still require time to do something similar. In the U.S. the government is putting pressure on VoIP companies to implement solutions or warn users of the problem. It isn’t recommended then, to expect VoIP to be reliable during an emergency.

None of the big problems with VoIP are without possible solution, so as VoIP continues to grow in popularity, workarounds and solutions will be implemented.

What’s interesting about VoIP is how flexible it is in terms of just what you use to make a call. Given that the Internet can be used, you can place a VoIP call using a piece of VoIP software on your computer. Alternatively, VoIP phones can be purchased. They are essentially a network device dedicated to making and receiving VoIP calls and will have their own IP address, like a computer. If you like your existing phone, you can purchase an adapter that allows it to be used as a VoIP device. Finally, you can combine all three, with a router providing your computers with an Internet connection, your VoIP devices Internet access and a means of hooking up your existing telephone hardware for use with VoIP.

Software based VoIP solutions, several of which are now available on the Internet, are often free to download and use. VoIP calls between users of the same system tend to be without charge. However, what happens when a call needs to be made to a traditional phone, or to somebody on a different network? First of all there’s the technical question: “can it be done?” Some services use proprietary naming and numbering systems that could make calling a different network difficult. However, for the most part it is possible.

So, you can make the call, but what will it cost you? If your VoIP provider is connecting to a landline then they’re going to be charged for it, and that charge will be passed on to you some how. The same is likely if you want to ring somebody on another VoIP provider. You’ll either have classic style per minute or per second rates, dependant on who, where, when and how long for. Alternatively, you might have a broadband style monthly fee with unlimited calls. Quite what service you go for will depend on what your friends and colleagues use, how often you’ll use the service and who you’ll be calling.