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GETTING INTO Last time we looked at wireless networking (January 2001), the term “Wi-Fi” didn’t even rate a mention. Things have moved on just a tad in that four-and-a-bit years! I n the past few years, there have been three major movements in wireless networking. One is speed – it’s now much faster; the second is availability – now much more equipment is available; the third is price – Wi-Fi equipment is now much cheaper. A lot of the equipment has also become smaller and the software to drive it has become more user-friendly. Before we go any further, let’s try to remove some of the confusion about the terms used for wireless networking. Wi-Fi and 802.11 Wi-Fi, which is an abbreviation of Wireless Fidelity (itself a pretty meaningless term!), is actually a registered trademark of the Wi-Fi Alliance, an organisation set up to ensure technical standards are maintainted. Strictly speaking, Wi-Fi should only be applied to equipment whose manufacturer is a member of the alliance. But rightly or wrongly, like so many computer and technical terms, Wi-Fi has already entered our language as a generic name in its own right. The Wi-Fi Alliance regulates the use of the Wi-Fi trademark, only allowing manufacturers whose equipment passes their rather stringent suite of tests (and who pay big $!) to be certified and use the name/bear the mark. While that control has been relatively successful in maintaining compatibility (they have about 200 member companies worldwide), there are now countless manufacturers who don’t bother joining the Wi-Fi Alliance but nevertheless produce (usually!) compatible equipment. To be compatible, the equipment has to comply with the standard of yet another organisation, the IEEE (Institute of Electrical and Electronics Engineers). The IEEE has many working committees. One of these is the 802 Committee, which deals with computer networks. A sub-group, the 802.11 Working Group, handles the specifications of Wireless Local Area Networks. Various Task Groups within the Working Group handle specific types of Wireless LANs and assign their group code, or letter, to the standards they develop. Thus there is an 802.11a task group, an 802.11b task group and so on (in fact currently there are a, b, c, d, e, f, g, h, i, j, k, m & n groups and possibly more). We’re really only concerned with the 802.11a, b and g standards here. Speed The first 802.11 standard (in 1997) was at the time con14  Silicon Chip sidered fast for wireless – 2Mb/s – but it was agonisingly slow compared to the hard-wired networks of even then. Moreover, it had significant technical problems, not the least being it allowed two incompatible spread spectrum standards (frequency hopping spread spectrum, FHSS, and direct sequence spread spectrum, DSSS) at the same time. So some 802.11 equipment could not talk to other 802.11 equipment. By 1999, the 802.11b standard was in place. It was faster but more importantly, discarded FHSS. Swww.dailo from then on, all equipment was at least theoretically compatible. As you can see, the 802.11b standard has been around for more than five years. 802.11g, introduced in 2003, is now rapidly overtaking 802.11b, mainly due to its much faster speed or throughput. Apart from speed, “g” has other advantages over “b”; for example, it is more efficient in handling reflected (multipath) signals. You will see various claims on speed for the two systems but these must be qualified or you may not be comparing apples with apples (no Mac pun intended). 802.11b is specified as having an 11Mb/s throughput or “raw speed”. For many reasons, mostly due to the way data is packeted and transmitted, the real throughput is usually less than half this, coming in at about 5Mb/s. On the other hand, 802.11g is rated at 54Mb/s but the real throughput is again less than half – around 20Mb/s. But that fourfold increase is certainly worthwhile. Both the 802.11b and 802.11g standards use the same frequency band, 2.4GHz. It was originally chosen because in the US it was an unlicenced “garbage” band (similar in some ways to the 27MHz band) therefore no licence fees would be required. The use of that frequency has proved rather unfortunate, because it is shared with a huge number of devices, from toys to cordless phones to microwave ovens. Therefore, wireless networks can, and often do, suffer interference (or cause it). One advantage, though, of 802.11b and g being on the same band is that 802.11g is backward-compatible with 802.11b; that is, a “g” device can talk to a “b” device and vice versa, albeit at the slower speed of the “b” system. “b” and “g” equipment operates on 11 channels (individual frequencies) between 2.4000GHz and 2.4835GHz. “g” equipment is generally more expensive than “b” – but we are not talking sheep stations. We’ll look at costs siliconchip.com.au ® A FEW YEARS ON... Part 1 – by Ross Tester a little later. 802.11a – an orphan? Despite its earlier alphabetical suffix, 802.11a effectively came about after 802.11b (in fact, the two standards were released simultaneously but the technology to support 802.11b came about faster). 802.11a seemed like a good idea at the time; a new standard operating on a higher frequency (5GHz, far from the madding crowd), with higher speed (54Mb/s raw speed or 25Mb/s real speed). Unfortunately, perhaps like the Beta vs VHS battle of last century, the best system doesn’t always win, due mainly to the inertia and marketing of the inferior system. It wasn’t helped when Apple’s CEO Steve Jobs said that “802.11a is doomed to failure”, justifying his company’s decision to base its AirPort Extreme Wi-Fi on 802.11g. That’s not to say 802.11a is dead in the water – far from it. It still has many proponents and users and prices have fallen significantly – but compared to 802.11b/g its use is miniscule. Maybe, in time, it will emerge a winner but at the moment, we suggest you stick with 802.11g (or b if you must!). There are systems which offer automatic dual band (a and b) and even tri band (a, b and g) operation (depending which one is in the area) but they are usually significantly more expensive. Long range . . . or maybe not! You will often see ranges quoted for Wi-Fi (yes, we’re using the generic) of “up to 300m”. Note that phrase “up to”. By definition, that means somewhere between zero and 300m but our experience is it’s much more likely to be closer to the former than the latter. If you expect to be able to plug in a Wi-Fi card, dongle, or stick into your PC or notebook and expect to be able to access another computer anything like 300m away, in Wi-Fi in the home means no messy cables to run and (theoretically!) you can use your notebook computer wherever you want. As we explain, it’s not always quite that easy – but worthwhile, nevertheless. (Photo courtesy of the Wi-Fi Alliance). siliconchip.com.au May 2005  15 Airports were very early adopters of Wi-Fi – especially handy since 9-11 when you have to book in for international flights 2-3 hours early. In some (limited!) airports, especially in the USA, Wi-Fi access is even provided free by altruistic managements. (Photo courtesy of the Wi-Fi Alliance). those immortal words of Daryl Kerrigan in “The Castle”. . . you’re dreamin! To achieve that sort of range, you’d definitely not want any walls in the way and you’d generally need to use some form of external antenna, probably with some gain (ie, directional). With much of today’s smaller Wi-Fi equipment (particularly for notebooks) the latter is not practical, as antennas are usually built in. However, our Kiwi colleague Stan Swan did describe fitting parabolic antennas to USB Wi-Fi sticks in his “WiFry” article in the September 2004 SILICON CHIP. So what’s the range? As they come out of the box, the typical range of most Wi-Fi devices is dramatically less than 300m – our experience for domestic installations (ie, with typical walls in the way!) is that 10m is about maximum on a good day with a tailwind! An example: my next-door neighbour and I share a broadband cable connection, linked via Wi-Fi. Our houses are side-by-side and his wireless access point is on a wall closest to my boundary. But there are very few places in my home which allow connection – any which do are on his side of my house. So we are talking less than 5m. Even he has problems accessing the system from many places in his home. He’s gone to the trouble of a higher spec (better performing) access point, higher gain antennas and so on. But the improvements were marginal at best. Oh, just in case you were wondering: yes it is perfectly legal to share a broadband connection with your neighbour. Messrs. Telstra, Optus and Co might not like it too much but sharing broadband (ADSL or cable) with a neighbour, via wireless, is a great way to not only keep the cost down but 16  Silicon Chip get a faster and higher usage connection into the bargain! Incidentally, we’re no lawyers but our reading of the relevant legislation suggests that it would be illegal to share a broadband connection with your next door neighbour via a wired network because the cable would cross your property boundary. With wireless, there’s no cable, so you don’t transgress legislation! We might be tempted to have a closer look at explaining how to do this in a future issue – but it’s not exactly rocket science! Wireless networking basics Before we go too much further, we should point out that we’re concentrating here on “PCs”; that is Intel/AMD etc machines running Windows, because they are, far and away, the most common/popular computers in both the home and the workplace. That’s not ignoring the Mac family – Apple has supported Wi-Fi for a long time with its AirPort and AirPort Extreme technology, to the extent where going wireless with a Mac is often easier than with a PC. (Yeah, go on Mac fans. So is everything else . . .) Having said that, perhaps Win fans need more handholding so be quiet, you Mac lot! (Why does a Mac mouse have only one button? ’Cos Mac users can’t cope with two . . .). At the most simple level, to connect computers together in a wireless network all you need is a wireless network adaptor in each computer to be wirelessly networked. We’ll look at various types of adaptors shortly. Wireless adaptor hardware When we covered this area back in 2001 there was very limited choice. The PC-slot cards we described were then quoted at around $490(!) (in 2001 they were known as siliconchip.com.au Setting up a business meeting with wireless networked laptops is easy – a simple ad-hoc system will do fine. All anyone joining the meeting needs is the WEP or WAP code and their computer basically does the rest. (Photo courtesy of the Wi-Fi Alliance). PCMCIA cards, which earned them the name of People Can’t Memorise Computer Industry Acronyms). While PCI cards are still available for desktop PCs – in fact, now very commonly so and really cheap, like anywhere between $10 and $50 – you have a choice of a range of other adaptor hardware, suitable for either desktop or notebook. That assumes, of course, that your notebook doesn’t have wireless inbuilt: all but the lowest end of notebooks these days now come with wireless as standard. But if yours doesn’t (like my IBM R40e!) you can “go wireless” via the aforementioned PC card, a USB “stick” which looks just like flash memory, or an Ethernet connection. PC cards now retail for a tenth (or less) of the 2001 price – you can often pick them up for $20 or less. Wireless USB sticks which, as late as last year, were selling for $100 or more, can now be sourced for much the same price as PC cards. Many notebooks/laptops use a “Mini PCI” card which connects internally and uses aerials which run up the side of the LCD screen, again internally. Some manufacturers include these aerials even if they don’t include the card (to save money) so a Mini PCI wireless upgrade is often a possibility. One big advantage (apart from being completely internal) is that the Mini PCI card usually consumes less power than other cards, important in a battery-operated computer. Another advantage is that the antennas usually (but not always) offer performance advantages over the tiny antennas inside USB sticks or PC cards. The one piece of wireless hardware we haven’t mentioned, although available, is an Ethernet port adaptor. This is an option for a desk-bound notebook or laptop but hardly the type of thing you’d go walking around town with – apart from the fact that battery operation isn’t ususiliconchip.com.au ally offered, it sort of takes away the portability advantage of a laptop/notebook! What about Bluetooth? Bluetooth, though certainly a wireless device, doesn’t really fit into this discussion because it is incompatible with the 802.11 standard (you may note that it is called neither Wi-Fi nor 802.11). In fact, Bluetooth’s incompatibility often causes interference problems for close-by Wi-Fi equipment, as it too occupies part of the 2.4GHz band. While its speed is only 1Mbps (or 700kHz true speed), significantly slower than even 802.11b, it doesn’t have the Ethernet-like overhead of 802.11b so is not quite as “bad” as those figures might suggest. It’s also much lower in range, with about 10m being the maximum you can expect. Bluetooth can be, and is, used for “ad hoc” style networking but is much more suitable for connecting other peripherals (video/still cameras, for example) into the computer system. And WiMax? We mention this here only because we have featured it in SILICON CHIP recently, although not by that name. You may recall our article on the “Unwired” wireless broadband system in November 2004. Unwired is an example of WiMax (and yes, it also has its own IEEE 802 working group – in this case 802.16/802.16a). WiMax is also an acronym – Wireless Interoperability for Microwave Access. It is not a short-range system as in Wi-Fi, it’s intended for relatively longer distance internet access via microwave (radio signals above 3GHz). For more information, refer to the November 2004 article (back issues available for $8.80 inc p&p). May 2005  17 A typical ad-hoc wireless network. No computer (or, as you can see, other devices such as PDAs), are any more “important” than any other. The computers simply talk to each other on demand. The advantage of an ad-hoc system is that it is very simple to set up and no extra hardware is required. But you can’t connect to another network nor to the internet using an ad-hoc network. NOTEBOOK WITH INTERNAL WIRELESS PC CARD PC WITH WIRELESS PCI ADAPTER NOTEBOOK WITH PLUG-IN WIRELESS PC CARD (PCMCIA) Add-in cards We’ve shown a selection of wireless hardware from a couple of well-known sources – Jaycar Electronics and Dick Smith Electronics (New Zealand). Most of these are 802.11g specification and cover both USB and PC card types. In all cases, you will note they have indicator LEDs which show both connection and wireless transmission. Again in all cases, drivers must be loaded before they will operate correctly – and we found it best to use the manufacturer’s software. All the adaptors shown below have inbuilt antennas (one can be varied in direction) so cannot be used with external (gain) antennas. However, some PC card adaptors can connect to pigtails which in turn can be used with external antennas. None of this equipment carries the “Wi-Fi” logo but all worked perfectly with other equipment which does. We’ve also shown a USB Bluetooth adaptor in this photo PDA WITH WIRELESS DESKTOP PC WITH WIRELESS PCI ADAPTER OR USB WIRELESS STICK, ETC so you can see the difference (and the similarities!). It’s significantly smaller than even the smallest USB stick shown here and this is normally the case.. Connecting your computers The first thing you need to do is decide which type of connection you want to make – and that depends on what you want to do. There are basically two wireless network systems – ad hoc and infrastructure. If you only want to be able to communicate between a couple (or a few) computers, say to transfer files between them, or use a printer connected to one computer on the network while at another computer, ad hoc is the way to go. It is relatively simple. However, if like most people you want to be able to connect your computers via wireless through another computer to the internet or even another network, you’ll need an A selection of low-cost wireless networking equipment. Far left are two 802.11b USB “sticks” with an 802.11g USB adaptor alongside (all from Dick Smith Electronics NZ – DSE Australia do not appear to have equivalent products but DSE NZ will mail order back to Australia – see www.dse.co.nz). Far right is a PC card 802.11g adaptor; alongside that is an 802.11g USB stick. At front centre, for comparison, is a USB Bluetooth adaptor (last three products from Jaycar Electronics – www.jaycar.com.au). 18  Silicon Chip siliconchip.com.au DESKTOP PC WITH WIRELESS CARD NOTEBOOK WITH WIRELESS USB “STICK” ACCESS POINT NOTEBOOK WITH WIRELESS PC CARD The difference between the ad-hoc wireless network opposite and the basic infrastructure wireless network shown here is obvious: the additional piece of hardware in the middle, called an access point. It is in turn connected to what might once have been regarded as a fileserver, ie, the main computer in the network. It is through this computer and its internal or external modem that connection to the big wide world (also know as the internet) is possible. While we have shown more devices in this diagram than are in the adhoc network, that isn’t necessarily so: in fact, many infrastructure networks will have just the main computer, the access point and a single notebook computer to give that notebook internet access. INTERNET VIA DIALUP, BROADBAND, ETC PC WITH WIRELESS PCI ADAPTER PDA WITH WIRELESS infrastructure setup. Infrastructure is more complicated, as its name suggests, because you need more hardware equipment than just wireless access cards. To some, an ad hoc network is not a “real” network at all, just a means of file sharing. “Real” networks are built on infrastructure. But the ad hoc method is a perfectly viable option, especially for home users not wishing to make it too grandiose. Because it is simpler, we’ll look at ad hoc first. Ad hoc wireless While it is possible to set up an ad hoc network using most versions of Windows, we strongly recommend using at least Windows 2000 and, if possible, Windows XP. The reason is that the latest Windows versions, XP especially, really make life easy when connecting to or building a network – and Wi-Fi networks are no exception. First, you need to install the internal Wi-Fi card (or USB stick or PC card or Ethernet adaptor) in/on your PCs, along with their drivers. In many cases XP will have a suitable driver but it’s usually best to install the one which came with the card because it will have the latest versions and also include any manufacturer’s “niceties”. Remember to power down the PC first if you’re installing an internal card. It’s not absolutely essential to turn off the notebook or laptop for (external) PC cards or USB adaptors but we’d do it anyway and so let Windows find the new siliconchip.com.au “MAIN” PC WITH MODEM hardware when it loads. Also, some hardware is quite specific about which order installation goes – some require the software loaded first then the hardware installed, others the opposite. And some don’t care! If in doubt, follow that age-old (but oft ignored) advice: if all else fails, read the instructions! Once installed and powered up, unless something is really haywire, Windows lets you know it’s found the new hardware, loads the driver and puts the appropriate entry in Network Connections in the Control Panel. From there it is usually just a matter of “follow the bouncing ball” – most software gives you a step-by-step run-through where it finds and identifies the wireless connection and allows you to connect to it. Naturally, this assumes you have already done this in another computer – otherwise there is no wireless connection to find! Some of the wireless network adaptors we have looked at strongly recommend turning off XP’s relatively automatic wireless networking and use theirs. We have usually found it is better to use the adaptor’s software because it either contains more (or later) features than XP or because it allows the card to be set up easier. Conversely, we have found software where, when something doesn’t work, it doesn’t work big time – and the only way to get around the problem is to uninstall and reinstall the system. But overall, setting up an ad-hoc network should be a relatively painless process. The main reason people have May 2005  19 This Wireless PCI card from Jaycar is typical of the cards available these days. It’s 802.11g, 54Mb/s standard and can take an external antenna. Note there is no Wi-Fi logo? problems at this stage is that the distance between computers is too great and it’s actually a lack of wireless signal that causes the problems. For this reason, when we’re setting up any sort of wireless network, if possible we do it with both/all computers in the same room. When the system is up and running, we move them to their usual locations and hopefully everything still works perfectly. Wireless ecurity We’re covering this here (before moving on to infrastructure networks) because it’s likely that once they’ve set up their ad hoc system, some users may not read any further. And wireless security is really, really, really important. Is that enough emphasis? Many computer users imagine that having anti-virus software and a firewall installed will protect them from intrusion. To some degree, they will – but wireless introduces some extra security problems, problems that a firewall will not help. (What? You don’t have anti-virus software or a firewall? I hope you don’t do any Internet financial transactions . . . and remind me not to read any emails you send me! Then again, they won’t get through mine . . .) By default, Windows will connect wireless without security enabled. Big, big mistake, if you value your data (and even more important when you go on to the next step, an infrastructure network with ’net access). The reason for this is that without security, anyone within range can also log into your network and either take a look around, steal data or do some real damage, if they’re feeling malicious – or all of the above. Snooping really is as simple as turning on their computer and searching for your wireless network (which the computer does automatically!). And that snooper doesn’t have to be particularly close – with a high gain antenna such as a dish aimed at you, they can be some distance – perhaps as much as a couple of kilometres – away. WEP and WPA Wireless networking (currently) has two main methods of preventing unauthorised access – WEP, or Wireless Equiva20  Silicon Chip lent Privacy, and WPA, or Wi-Fi Protected Access. WEP, the older system, is somewhat similar to the security encryption used over a wired network; the difference is of course that it’s quite hard for someone to “tap into” your wired network, especially contained inside a building. Wireless, which by and large doesn’t respect walls, makes it that much easier. WPA is much newer and more secure, so of the two, WPA is by far a better choice than WEP but it’s not always available. Worse still, many people don’t even bother to use even WEP because (a) they are lazy, or (b) they haven’t quite got around to enabling it, or (c) they don’t understand it. (WEP is much better than no security at all, protecting from casual snooping but anyone who knows what they are doing can break WEP fairly easily). WPA comes as a patch with Windows XP Service Pack 2 (XP SP2) which, of course, every XP user should have installed. It’s a free downloaded from www.microsoft.com and we would suggest you do it! WPA unfortunately won’t work with all wireless hardware, especially some older types. In some cases this can be overcome by obtaining the latest drivers for your particular hardware (almost invariably, the setup disc or manual will include a manufacturer’s URL so you can download). If for some reason you’re still running XP SP1 or Windows Server 2003 you’ll need to download and run the WPA patch, again from Microsoft. Where WEP relies on you entering (and remembering!) an obscure hexadecimal number, WPA allows you to enter a plain-text password. It then mathematically generates the encryption key from that. If a snooper manages to find out your password (eg, because you’ve written it on the whiteboard next to your computer in plain view of the outside window!) they can still access your network. But they can’t easily decipher the password from your network data, as is possible with WEP. Our advice is to ALWAYS use security – at least WEP. You can use either 64-bit or 128-bit encryption – the latter is more secure but still not unbreakable. But at least it will discourage the casual snooper. If you can, use WPA. Infrastructure mode security The preceding comments about security apply even moreso if you are setting up an infrastructure mode wireless network and accessing the internet. This is of course the main reason for setting up an infrastructure mode network, though you could be doing it to gain access to another network, etc. Therefore, if an intruder manages to get into your wireless network, they will also have access to the ’net and be able to cost you real $$$, especially if they start downloading movies and music, for instance. Or they could use your system to send harmful email, spam and so on, place bogus orders charged to you or run a variety of scams and you would get the blame as the source. So enable that security! Access points/gateways The main obvious difference between ad hoc and infrastructure mode is that you (usually) need another piece of hardware, usually called an access point or wireless gateway, which connects to the computer containing or attached to your modem and thence internet connection. siliconchip.com.au You’ll also see references to these devices in your Wireless travels. Like many things in wireless, devices tend to mirror the devices found in wired networks. In a “star” network (as distinct from a peer-to-peer) there is a central device responsible for handing out data to all of the computers in the network. It’s sort of like a bike wheel, with all the spokes coming back to a central point. That’s the hub – and in networks, there are three basic types. A passive hub does little more than send the data it receives back out again. While simple and cheap, it costs a lot of bandwidth because the passive hub doesn’t know which computer on the network is supposed to get the data – so it sends it to the lot. A switching hub, on the other hand, reads the address on each packet of data and sends it to the correct computer. Therefore it doesn’t cost a lot of bandwidth. A switching hub is often abbreviated to simply a “switch”. An intelligent hub has the smarts of a switching hub but goes one step further by allowing a network administrator a lot more control. Only if you have a large network (eg, in a big organisation), with someone looking after it, would you need one of these devices. Just like wired networks, hubs and switches are found in wireless networks, doing very similar jobs. Bridges are a bit different to hubs and switches. They transfer packets of data from one physical medium to another. That might be two different networks, for example a wired network and a wireless network. They don’t do anything with the data packets except transfer them – they don’t read them to work out the address, for example. While bridges are very commonly available as standalone devices, for our purposes (remember, we’re talking about wireless!) the most common place you’ll find them is actually part of a wireless access point. They then allow the wireless network and a wired (ethernet) network to talk to each other. Routers and gateways We said a moment ago that bridges merely transfer data packets – they don’t read it as such. But there are types of bridges that do and they’re called routers. As their name suggests, they do read the data and determine where it is siliconchip.com.au www.elexol.com www.elexol.com www.elexol.com www.elexol.com www.elexol.com www.elexol.com Hubs, switches and bridges www.elexol.com www.elexol.com www.elexol.com www.elexol.com 2nd Generation Low Cost USB Data I/O Module Need to get data into or out of a USB port? Here’s what you need 24 independently programmable Input/Output pins grouped into 3 ports. Single module high-speed digital Input/Output solution. Up to 128 modules can be connected to a single PC with capabilities of further expansion. Easy to connect by 0.1” pitch headers to suit standard IDC connectors. Integrated Type-B USB connector. On-board unique serial number in EEPROM and custom programmable FLASH microcontroller. Both USB enumeration information & microcontroller can be re-programmed to suit customer needs. Module powered by the USB from the PC. NEW! UPDATED V3 MODEL HAS ON-BOARD LED INDICATION Just some of our range of USB and MP3 modules ... USB MOD1 - USB MOD2 USB MOD3 - USB MOD4 - MP3 MOD4 USB Plug and - USB Plug and USB Plug and USB Plug and -VS1001 chip. Play Serial Development Module. Up to 920k baud (RS232) and 2000k baud (RS422/RS485). www.elexol.com www.elexol.com www.elexol.com www.elexol.com www.elexol.com www.elexol.com Access points usually provide just the single connection and are now becoming quite cheap. When we looked at Access Points in the January 2001 article we quoted a price of $1155.00 – they’re now readily available at sub $100 for a “no frills” model. Wireless gateways provide the same connection but also may have more than one port to enable you to connect to another, usually wired, network. They are also a bit more expensive. The choice, then, is an access point if you merely want to connect your wireless network to the internet, or a wireless gateway if you want to connect to another network and to the ’net. A little while ago we said that an access point is another piece of hardware – but this is not necessarily so. Access points can be entirely software based – but it’s more usual (and often simpler) to go the hardware route. Play Serial Play Parallel 8-Bit Play Parallel 8Converts Development FIFO Bit FIFO clocked serial Module (2nd Development Development data (MP3) to Gen). 1000k baud Module (2nd Module. stereo audio (RS232) and Gen). Up to 8 out. Suitable for Up to 8 Million 3000k baud Million bits bit (1 Megadriving byte) per sec. (RS422 / RS485). (1Megabyte) per headphones.SC second. Visit our web shop <at> www.elexol.com Elexol Pty Ltd Ph: (07) 5574 3988 Fax: (07) 5574 3833 (PO Box 5972, Bundall, Qld 4217) www.elexol.com www.elexol.com www.elexol.com www.elexol.com supposed to go and then send it to that destination. In fact, in some ways you might regard the internet itself as a huge collection of routers, which read data packets and send them on. Of course, there’s a lot more to the ’net than that but it gives you some idea of data routing. Reading then routing data takes time so invariably, routers cost time and bandwidth. It would be unusual for a home or even medium-sized corporate wireless network to need the services of a router. While English and Australian pronunciation of the word “route” might suggest an alternative, invariably (for we hope obvious reasons) we stick with the American pronunciation where routers rhymes with “shouters”, not “shooters”! And now we move onto gateways. What are they? Good question. Probably the best answer is (usually!) a device which combines most, if not all, of the functions above – and perhaps a few more. Gateways can be, or have the functions of, hubs, switches and routers – and may even add additional hardware features such as built-in modems, firewalls and perhaps a DHCP (dynamic host configuration protocol) server and a NAT (network address translation) gateway. If you don’t know whether you need a gateway or not, chances are you don’t! SC What’s in Part 2? We’ll go through each of the steps (and traps for young players) in setting up both an ad-hoc and an infrastructure wireless network. May 2005  21