BOOT CAMP 388 (02/08/05)

Wireless Networking, part 2

Following on from last week’s introduction to ‘Wi-Fi’ technology, this week we’ll be looking at the extra hardware you will need to set up a simple wireless network to connect two or more computers together so that they can share an Internet connection and printer and exchange files.

As we saw in part one wired and wireless networks work in broadly the same way and the similarities extend to the principle components, which in a typical small home or office network are the ‘router’ and the network ‘adaptors’.

A network router is a sort of telephone exchange for data, acting as central switcher or ‘hub’ through which information passes on its way to and from the computers connected to the network. A network adaptor is the simply the interface or connection point between a PC and a computer network.

In a conventional wired network the router is connected to the adaptors by cables; the only real difference with a wireless network is that the Wi-Fi router sends and receives data over a short-range radio link using a device called a transceiver, which communicates with matching transceivers or Wi-Fi adaptors connected to each PC.

There are several possible configurations for a wireless network but the most straightforward arrangement is to connect the router, by a short network cable, to the main PC or ‘server’. This will normally be the one with a broadband Internet connection and the resources that the other PCs or ‘clients’ want to share.

A simple wireless network using a basic Wi-Fi router will do just about everything that most users might want but it has one fairly obvious limitation. The server PC will have to be left switched on all of the time in order for the other PCs to access the Internet. That’s because most low-cost broadband/ADSL modems -- the sort generally supplied by ISPs -- use a USB connection to the server PC, which provides the modem with power and software support.

It’s not a huge problem and this the kind of undemanding job that’s well suited to an old or redundant PC but it would obviously be better if the Internet connection were always available, without having to leave one PC running all of the time.

There are a couple of solutions; the easiest one is to use a combined Wi-Fi router and broadband/ADSL modem; prices start at around £60. The alternative is to use a standard Wi-Fi router with a ‘network’ broadband modem. These are a little more sophisticated and slightly more expensive than regular USB modems. They have their own power supply and operate independently of the PC. Instead of a USB connection they have a network socket so they can be plugged directly into the router. That means the broadband connection is always live and available to the PCs on the network, even if the server PC is switched off. The only drawback is that it may be necessary to install extra some software on the client PCs and this will usually be supplied with the router. For more information about changing broadband modems see this week’s Top Tip.

There are several different types of Wi-Fi adaptor. The commonest forms are a small module or ‘dongle’ that plugs into one of the PC’s USB ports or a PCMCIA type PC ‘card’ and these can be used with most laptops. Wi-Fi adaptors can also be built into a computer, either as plug-in card that fits into a spare PCI expansion socket on a desktop PC’s motherboard or, in the case of some recent laptops, the Wi-Fi adaptor is incorporated into the motherboard (or a small module fitted inside the case).

Wi-Fi adaptor prices start at around £25 for basic 802.11b (see part one) PC cards and USB dongles; faster 802.11g adaptors are normally only a few pounds more but remember, you will need one adaptor for each PC in the network, except possibly the server, which as previously mentioned can be connected to the router by cable. It’s also worth mentioning that most Wi-Fi routers have several cable network sockets (usually four) so you can mix Wi-Fi and wired network connections. For example, if one of the PCs is physically close to the router it will cheaper and probably a lot simpler to connect it using a cable.  

Wi-Fi components are normally sold separately and if you shop around there are some real bargains to be had. However, for those new to wireless networking I strongly recommend buying a wireless network starter kit that will include a Wi-Fi router (or combi router/ADSL modem), one or more matching Wi-Fi adaptors plus any necessary software and cables. A kit avoids the possible pitfalls of mixing and matching components from different manufacturers. Kits may cost a little more but they are designed with beginners in mind and come with simple step by step instructions. Once you have your network up and running there should be no problem adding extra adaptors from other makers, provided of course they conform to the same Wi-Fi standard. 

Next Week -- Wireless networking, part 3

JARGON FILTER

ADSL

Assymetric Digital Subscriber Line -- technology used to send high-speed broadband data down ordinary telephone lines

DONGLE

A type of electronic key (‘dangling’ on the end of short wire) used to unlock some types of software or any small device that plugs into a PC

TRANSCEIVER

A combined radio transmitter-receiver

TIP OF THE WEEK

There’s usually no reason why you have to use the broadband modem supplied by your ISP, however network modems work in a slightly different way to USB modems, which are normally set up using a configuration program that runs on the PC to which they are connected. A network modem will have its own local Internet Protocol (IP) address and is configured using an Internet browser. Once the address has been entered in the browser window (usually something like http://192.168.0.100) the modem asks for a password and PIN and then displays a set of web-like menu pages into which your broadband service name and password can be entered. 

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