Overview: What it’s about and a touch of history
VoIP?
VoIP - The first question - how do you say it? The easy answer is that you can pronounce it as Vee Oh Eye Pee, or just say it like Voyp (just a short voyp, not voy pee) Either way seems acceptable, although the latter seems to be more popular.
What does it mean? The acronym stands for Voice over Internet Protocol, but simply put; it’s a way to transmit voice (and sometimes video) over The Internet. The generally touted advantage is that it’s free, although when you bridge the Internet to the existing PSTN telephone service you usually have to pay in some form or another.
History and principle
VoIP is not new. It’s been around since the early 1990’s, (and the telephone companies have been carrying voice digitally for a lot longer than that) however back then the technology and the Internet wasn’t quite ready and the whole idea got quietly forgotten by most people until relatively recently.
The principle is simple - digitise your speech (turn it from analogue format into a digital format) and transport it over the Internet to the far-end where it gets converted back to audio format, and vice versa, at the same time. The “same time” part is important - this gives what we call full duplex communication. In a half duplex situation, only one person can talk at any one time - like an old style “walkie talkie” and you end up saying “over” when you’ve finished speaking.
Another important feature is timing - often overlooked. We need to make sure that we send the data at the right time (and in the right order!) We can buffer up a few packets of data to cope with small delays (called “jitter”), but remember speech is real-time - if it started to get …. delayed …. then we might …. start to …. sound like captain …. Kirk!
More general information
For anything more than a simple person to person communication, you also need to provide some sort of switch, or an exchange and a service that lets you “dial” a number… Then things to start to become rather complicated… We won’t deal too deeply with the internal nuts & bolts here though.
In the world of VoIP (and telephony in general), it’s important to know that there are several conflicting systems although they can be put into 2 broad categories. Firstly there are the proprietary systems, and secondly there are the open systems.
The proprietary systems are developed by companies with a commercial interest in protecting their technology so they can maximise profits by locking people into their system which are incompatible with other companies systems. This has it’s good points as well as bad points. On the plus side, it gives you a single manufacturer to complain to if it shouldn’t work and all components should be guaranteed to work correctly together. On the down side, there is only one person you can buy from and you are stuck with that vendor and their pricing/licensing plan which can make changing to a new system (or even upgrading an existing system) quite a costly exercise. The traditional proprietary systems also tend to be relatively conservative in their approach too, and can be slow to adopt the latest features and technology.
The open systems use publicly available formats and protocols which allow a huge amount of flexibility in terms of the hardware, telephones, software, etc. that you can use with them. You are not stuck with one vendor and all telephones and other devices which comply with the published standards should work. Because it’s an open format, it means that anyone can use it, adapt it to their own systems and recognise and adopt the latest technologies relatively easily. Vendors of open systems can tailor the systems to your exacting needs and it need not come with the licensing overheads that the proprietary systems are encumbered with.
