Jan 212012

Computer clients have asked me several times recently “what is the difference between WiFi and 3g?”

concentric blue arcs representing wifi access

A popular symbol representing WiFi access. There doesn't seem to be anything similar for 3G access.

WiFi is a standard of localised radio transmission that is used to establish a wireless internet connection between a router and a device (computer or similar). So, your Internet Service Provider (your ISP – eg BT, Virgin, Zen etc) provides your internet connection to your premises via your telephone line or via a separate cable. The telephone line or cable is then connected to your modem/router (usually just called a “router” these days). Most routers can then connect computers to this internet connection either by ethernet cables or wirelessly or both. The range of the WiFi wireless connection is quite limited. This can sometimes cause problems in getting a signal to different rooms in the same premises. You pay for this WiFi access as part of your contract with your ISP.

3G, on the other hand, is a standard for transmitting radio that comes from mobile phone masts. In other words, it uses the same infrastructure as your mobile phone voice connection. It is run by the mobile phone companies and you need to have a device that will connect to a specific company’s 3G signal and a contract whereby you will pay the mobile phone company for using the system. Your 3G connection will give you access to the internet just as your WiFi connection does.

So, if you are at home and using your computer with a wireless internet connection then the normal way to do this is to connect to your router by WiFi. If you are out and about with your smartphone and want to connect to the internet then you will typically connect using the 3G service on your mobile. The upside of 3G is that you can (hopefully) get a 3G connection wherever you are, whereas your WiFi signal only works within close proximity to your router (eg at home). The downside is that the 3G connection can be very much more expensive to use and the 3G service is a bit wobbly. Sometimes you may not even get a 3G connection at all and sometimes it is excruciatingly slow. It can be even worse if you venture outside of London.

So far, it seems as if WiFi and 3G are very separate things for separate devices, but that’s not the case. Take the iPad for instance. All iPads come with WiFi connectivity, but for an extra £100 (gulp!) you can also have 3G connectivity on the same device. Why have both? Because 3G gives you flexibility to connect when away from your router and WiFi gives you affordability when you are close to it. Smartphones also have WiFi accessibility as well as 3G. Kindles come in different flavours as well, and if you have a model with 3G then Amazon provide your 3G connection free of charge. I’m not completely certain, but I think that any device that has both WiFi and 3G connectivity will automatically use the (cheaper) WiFi connection if it is able to do so – ie if it is in range of a WiFi network for which it has the passkey.

Blue WiFi symbols on photo of coffee barAnother common way in which these communications methods merge with the different hardware is in the use of “dongles”. These days, a “dongle” usually means a small USB-connected wireless receiver that provides a computer with internet access via the 3G system. Again, the 3G service (and the dongle) is provided by the mobile phone company of your choice. This is actually a very straightforward way of getting internet connectivity when away from your router but, again, it can be very expensive and the service can be wobbly. You can use these dongles either on a monthly contract or “pay as you go”. The monthly contract is not going to be much higher than your mortgage repayment. The “pay as you go” sounds great until you discover that it expires if you don’t use it. It’s a bit like buying a tin of ham to keep “for emergencies”, only to find that it’s disappeared from your cupboard because you haven’t eaten it within a month. The words “rip” and “off” come to mind.

There are other combinations and possibilities. A lot of smartphones have the capability of connecting to the internet with 3G and then sharing this connection with (for instance) a laptop computer. This is known as “tethering” and it’s my own chosen method for connecting to the internet when I’m out and about. If you want to do this, though, you must ensure that both your mobile phone and your contract with your mobile provider permit it. Things may have changed now, but I do know that a few years ago T-Mobile (in my own case) expressly forbade tethering in most of their contracts and they even “crippled” the phone’s capability to do it on phones that they themselves provided. I’m not sure, though, if that’s still the case.

Yet another possibility is that if you have Windows 7 you can turn that computer into a Wifi Hotspot so that any internet connection it is receiving can be made available to any device close by. I could capture an internet connection using the 3G of my smartphone, pass that to my (tethered) netbook and then broadcast a WiFi signal that I could pick up on my virtual iPad (so-called because I haven’t got an iPad). So, with all this I could save £100 when buying an iPad because I wouldn’t need the 3G connectivity. The downside, of course, is that by the time I get that all set up and working in Cafe Nero or Costa Coffee, then my coffee will be cold and it’ll be time to leave for my next appointment. Besides that, of course, do I really want to look like a super-annuated uber-nerd?

PS: …. and I haven’t even mentioned Mobile Hotspots

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Computer Support in London
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