Silicon ChipVoice Over IP (VoIP) For Beginners - September 2004 SILICON CHIP
  1. Outer Front Cover
  2. Contents
  3. Publisher's Letter: High voltage warnings err on the side of caution
  4. Feature: Voice Over IP (VoIP) For Beginners by Ross Tester
  5. Feature: WiFry: Cooking Up 2.4GHz Antennas by Stan Swan
  6. Project: Bed Wetting Alert Sounder For Toddlers by John Clarke
  7. Project: You’ve Had Your Fun – Now Make A Doorbell by John Clarke
  8. Project: PICAXE The Red-Nosed Reindeer by Clive Seager
  9. Project: Build A Programmable Robot by Thomas Scarborough
  10. Project: Oh No! Not Another CFL Inverter by Design by Branko Justic, words by Stephen David
  11. Vintage Radio: This Little Nipper was a dog by Rodney Champness
  12. Back Issues
  13. Advertising Index
  14. Outer Back Cover

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How to call lo FREE or Hands up if you’ve heard about VoIP technology. Keep those hands raised if you knew that with a personal computer and internet connection, you could make very cheap – or even free – long-distance and international calls. Mmm. Not quite so many hands up now? I n the “New Products” section last month, we featured a USB “NetPhone” from MicroGram Computers, which allows any computer with an internet connection to effectively become its own international telephone exchange. Well, slight exaggeration perhaps: nevertheless, it does allow you to make (and receive, of course) “phone” calls to and from anywhere. We’ll look at how this works a little later. But this is an example of a technology that very few people, except those “in the know” are aware of. Yet! It’s called VoIP – Voice over IP. What is VoIP? It is no more, nor no less, than its name suggests. Voice (predominantly telephone-type by Ross Tester 8  Silicon Chip siliconchip.com.au ong distance P2P VoIP For Beginners calls) sent over the internet (IP stands at your computer and sent via your How about WiFi? There are some altruistic WiFi sites for Internet Protocol). internet connection to anyone on the In a normal telephone call, made via planet who has also has an internet around which allow you free internet access (yes, there are a lot more which what is known as the POTS, or plain connection. old telephone system (also known Many references claim that you need charge but many are free – at last count as the PSTN, or public switched tela broadband or high-speed internet about 3700 in Australia with almost 900 of those in Sydney, according to ephone network), your voice is conconnection to make this work. verted (via a microphone) to an analog Trust us, you don’t. A plain old dial- www.sydneywireles.com). Grab a notebook computer with electronic waveform, routed via a vaup is good enough (as long as the speed riety of telephone exchanges to where stays up near 33.6kB/s). The downside WiFi, log in, plug in your headset or you want it to go, then converted back is, of course, that you pay a local call NetPhone and now you do have totally to audio (via an earpiece) at the fee every time you make an internet free international phone calls. We’ve all heard the stories about backpackers receiver end. and students using the ’net Well, at least that’s the “I knew it was over wh en I downloaded to tell colleagues about “broway telephone systems used Skype. When the inve ken” public phones which to work. ntors of KaZaA ar e distributing for free allow free international calls. These days, especially a little program No need any more: they for long distance calls, the that you can us e to talk to anybody can use the ’net itself to make chances are that it works else, and the quality is fantastic, and those international calls withthat way until the telephone it’s free – it’s over. Th out breaking any laws! exchange, whereupon the e world will ch ange now inevitably.” analog signal is digitised Is it legal? and converted into “packMichael Powell, Chai Speaking of breaking laws, ets” of data, routed to where Federal Communicat rman, US it’s often asked if you are doing it has to go as a digital sigions Commission just that by making free calls. nal, then converted back Not at all: VoIP is absolutely to analog at the receiving phone 100% legal. You are not stealexchange and finally, sent to the receiver as an analog signal. call. ADSL/Cable is “always on” so ing anything. You are not misapproRecently-released figures suggest you can make that call effectively for priating anything. You are not even using something in a manner for which that Telstra is currently converting at nothing. least 20% to digital but this is likely to OK, you still have to pay the it wasn’t intended. You are using the dramatically increase soon, if it hasn’t monthly ISP ADSL/Cable connection internet exactly as it was planned – done so already. fee. But you’re going to do that any- sending and receiving packets of data What P2P VoIP does is exactly the way, so we reckon the “free” claim is around the world. It just so happens that the data, in same – except that it is done right perfectly valid. siliconchip.com.au September 2004  9 this case, is a fully encrypted, digitised Similarly with multinationals: with read this! The other reason, of course, version of your voice (or someone VoIP, an office manager in Liverpool, is that VoIP, or at least its implemenelse’s voice that you talking to!). Australia can pick up his phone and tation, wasn’t particularly common All you are doing is effectively bytalk to a colleague in Liverpool, Engknowledge! And we’re changing that, passing the POTS/PSTN (even though land – and the company telephone bill right now! you are using a phone line to get to will not be bothered one bit! If you regularly talk to someone the telephone exchange and thence One research company estimates overseas and your telephone bill is, to the world via the net). As far as the that around 4% of international say, $100 month, P2P VoIP will have telephone exchange is concerned, it’s corporate telephone communication you well in front before the end of the all data. is now via IP but this is expected first month. Now that is some saving! Because you are not going through to rise to 44% within three to four Less frequent callers will make less the exchange as such, you aren’t going years – it’s largely just a matter of savings – but you will make savings through their pesky metering systems companies getting off their leatherbecause calls can be totally free. which normally result in you receiving bound backsides. All I can say is where was VoIP nasty letters each month. VoIP starts getting complicated when number one son spent five years Again we must mention that dial-up with big companies and common swanning around the globe and his connections will cost you at least a names – just recently we heard of a mother told him to call whenever he local call. And if you’re on a timed uscompany with about six John Smiths liked, reverse charges . . .? age plan (ADSL or dial-up) as distinct in Australia, confusing enough, but P2P Networks from a “per MB/GB” or “unlimited” now has about 60 John Smiths around plan, using a NetPhone will eat into the world on its VoIP system! While traditional VoIP systems have your time, just the same as any ’net Until recently, corporate VoIP been very good within an organisation usage does. equipment hasn’t been particularly using its own network, VoIP calls to If you make regular overseas calls, cheap – but certainly cheap enough to “ t h e outside” have not been as sucyou will almost certainly find it pays cessful. For one thing, call to get a broadband net concompletion rates have been for calls belongs nection, which you can too low, due in part to the use “The idea of charging s ve gi e ar ftw so e theoretically get these days of firewalls and also the use of yp Sk to the last century. in y sta ly for less than $20/month. I Network Address Translation ab rd fo af w power to by say theoretically because people ne (which renders over 50% of ily m fa d an ds touch with their frien r technology and at home I had to settle for residential computers unable ei th of e ag nt va ad much-more-expensive cable to communicate with trading ki ta ts.” en stm ve broadband because Telstra tional VoIP software). in ity tiv ec conn claimed “incompatible inThis is changing very quickNiklas Zennström, Skype frastructure” when I applied ly with the emergence of peerfor ADSL! to-peer (P2P) networks. CEO & Co-founder of In a P2P network, the How can Telcos allow operator takes advantage of the fact free calls? warrant its installation, given the huge that thousands of computers (perhaps savings made down the track. hundreds of thousands or more) are Quite simply, they cannot stop it. We’re not particularly concerned logged on to the network at any given They have bent over backwards to try with corporate VoIP in this article. time. to get Australians on the net. Then they There are plenty of organisations These computers share the network tried equally hard (and are still trying) around who are more than able to workload – traffic routing, processing to get Australians onto broadband. help out corporates with anything and bandwidth-intensive tasks that Well, VoIP is one of the un-publithey need. What we are interested in would otherwise be handled by huge cised benefits of an internet connechere is VoIP for the average (ie home/ (read expensive!) central servers. tion. small business/etc) computer user – By spreading the data crunching We’re quite sure Mr Switkowski and eg, you and I! around the networked computers the co would much prefer media such as operator doesn’t have to invest big SILICON CHIP would keep quiet about VoIP for the masses . . . dollars in computer infrastructure. VoIP so they could keep their nice litCost is almost certainly one of It’s a system that has become poputle earner (long distance and overseas the main reasons that VoIP has been lar amongst computer users over the phone calls) going. Now you know relatively slow to take off outside the last few years for so-called “file sharabout VoIP, you don’t need to feed corporate area. It’s only fairly recently ing” networks – eg, KaZaA, Napster, their coffers as much! that equipment low enough in price etc – because it appears they are getHow long’s this been going on? has become available for the aver- ting something for nothing. VoIP itself is nothing new. It’s been age person to start taking advantage That’s not strictly true, of course: around for years. A lot of the large corof VoIP technology and start making they are contributing some of their porates with offices in various states savings in phone calls. own computer power to the network to have been using their own intranets And the software to make it hap- make it happen. But as no actual coin for VoIP calls, saving themselves pen hasn’t been commonly available. of the realm needs to change hands, thousands of dollars in STD charges. That’s all changing, literally as you to most people it’s “free”. 10  Silicon Chip siliconchip.com.au Of course, the actual files shared via P2P could, in many cases, be illegal copies but it’s not so much the content of P2P we are looking at; it’s the way the system works. And while courts in the US ruled against Napster in the most celebrated P2P case, a recent court decision in Canada has gone the other way, ruling P2P networks (and file sharing) as quite legal. This mainly concerns the music and video industries and should not affect services such as P2P VoIP. Calls to “normal” phones So far, all we have considered are P2P VoIP calls between two suitablyequipped computers. But VoIP is capable of much more, including phone calls to “normal” (POTS/PSTN) phones and even mobile phones – again, anywhere in the world. Unlike the PC-to-PC variety, there is a cost to these calls, as it involves using a telephone service provider to connect into the phone system at the far end. But invariably, the cost of such calls is a fraction of the normal longdistance or international call cost – as much as 90% off! VoIP achieves this by using the ’net for the majority of the call distance, and then connecting into the phone system at the far end. So it’s almost as if you are making a local call. Calls are usually costed by the minute. But one “carrier” which we’ll look at shortly has rates of about three cents per minute to a variety of major countries, such as the UK, USA, Canada, Ireland, NZ, China, Singapore, much of Europe and Asia and many more (23 in all), including Australia (rate current as at 1st August 2004). The downside, admittedly minor, is that most calls are charged by the minute, so a 5-second call to a wrong number, fax, answering machine, etc will cost you the full one minute rate. Aw, shucks – a whole 3c wasted! Calls to mobile phones Even more importantly when friends and colleagues are travelling around the world, calls to mobile phones in many of the overseas countries are at the same 3c/minute rate. Regrettably, Australia isn’t one of those countries – it’s about 30c per minute. Still, that’s about 25% less than the typical fixed-to-mobile rate of most service providers in Australia siliconchip.com.au – and there doesn’t appear to be any “flagfall” charge. So it would appear that you can call a local mobile phone from your netphone and save a significant amount of money. Call quality There has been criticism about the quality of VoIP phone calls – tinny or unnatural sound being one of them. My experience, with recent equipment, is exactly the opposite. My NetPhone calls are not just better quality, they’re significantly better quality than the same call with a POTS/PSTN phone. In fact, much better voice quality is one of the selling points of the netphone I am using, the K1000 which came from Microgram Computers. I have read of problems calling international mobile phones using dial-up internet – dropouts, truncated speech, etc – but this could have been a slow dial-up connection problem. At the time of writing, agreements with service providers had just been signed, coinciding with the launch of the netphone-to-POTS/PSTN/mobile service. Latency One problem you often read about with netphones is latency – the delay in your voice reaching the other end and vice versa. Latency can range from an echo effect to a real long delay. The delay depends largely on the distance your call has to travel to reach you. You don’t know whether it’s being routed between many, many countries or maybe just a few. Personally, I haven’t found latency a problem. That’s not to say it doesn’t exist – I just haven’t found it a problem! There is also some latency on net-tophone calls but again, my experience is that it’s no worse than on international phone-to-phone calls. Sometimes it’s noticeable, sometimes not. In calls I’ve made to Australian phones, it appears the latency is about 0.5 seconds or so. It might take some people a little getting used to but if it annoys you too much, go back to wasting money on your old-style international and long-distance calls. Dare I say it: it’s your call! Latency is reported to be worse when calling mobiles, particularly those on the other side of the world but so far I haven’t found anyone to call to test it out! (Hey, does someone on a mobile “over there” wanna Skype me?) VoIP Telephones Not yet at all common in Australia but starting to emerge overseas are dedicated VoIP phones – phones which don’t need to connect to a computer and act, for all intents and purposes, like a “normal” phone. Their secret is simple: like any other internet device such as web cameras and the like, they have their own IP address and can be addressed directly from the ’net. You’re sure to see these phones in this part of the world before very long at all. Wot, no netphone? You don’t even need one! While the netphone makes calling very convenient (and everyone is comfortable with using a phone!), all you need is a headset (microphone/earphone) which plugs into your computer sound card. In fact, in some ways it’s even better than a netphone because the earphone and mic give you even better quality. As we’ll see shortly, all the “calling” can be taken care of by mouse clicks, including (if you want) calls to POTS/ PSTN phones. Give it a go! Now let’s look at this again. The software is a free download. You may already have a headset – if you don’t they are available for next-to-nothing. Even buying a Netphone won’t cost you a fortune. If you’re on broadband, it’s not going to cost you any more – dialup will, but not very much. So where’s the catch in making free international or long distance calls? There is just one: getting your partner/kids/etc off the computer when you want to use it, just like getting them off the phone when you want to use it! (Of course you can continue to use the PC while they’re talking but they don’t want you listening in. . .) Apart from that, we cannot think of any reason NOT to jump into P2P VoIP! OVERLEAF: How YOU can do all this, using free “Skype” software! September 2004  11 Want free calls? You wa What is Skype? Starting Skype Simply, Skype is one type of software which drives P2P VoIP. You download Skype, install it and you are ready to go. It’s a 9MB free download, available from www.skype.com We should point out that Skype is but one of many P2P VoIP services available. It just so happens that from our investigations, we believe it’s the best around, if not only because it is free to download and free to use, at least as a P2P system. That is, calls between computers running Skype, where ever they are, will cost you nothing. It also has many features which other P2P VoIP systems cannot claim. Skype was created by Niklas Zennström and Janus Friis, founders of KaZaA (www.kazaa.com) – reputed to be the world’s most popular Internet software. Their experience with KaZaA – itself a peer-to-peer system which allows users anywhere in the world to search for and share files – placed them in good stead when it came to developing Skype. Skype has no advertising, no popups and as far as we can see, no nasties. Zennström and Friis have publicly stated that the P2P section of Skype will remain totally free of charge. Skype has brought on a whole new lexicon. You no longer call friends and colleagues via your computer. You Skype them! And using your PC to Skype is, logically enough, called Skyping. Think those names won’t catch on? Don’t bet the farm on it! Once downloaded and installed, the software will ask you for a Skype Name and password. You can make the user name your own or, if you wish anonymity, you can make up any name you like of at least six characters, no spaces (assuming it hasn’t already been taken, of course). After you have selected a Skype Name and password, you will be asked to fill in a personal profile. Entering information in the personal profile is optional and if you chose to make the profile available to other Skype users, then they will be able to search for you using this information. You can edit this profile at any time; even include a photo of yourself if you wish! Skype doesn’t store your personal profile: it is shared out to other Skype users when you are on the network Skype will not show your “online” or “offline” status to any other user unless you have specifically authorised that person. It’s just one way to protect your privacy but it doesn’t stop that person Skyping you if they have your Skype name. Hardware requirements Skype’s minimum hardware requirements are quite modest: a PC running Windows 2000 or XP with a 400MHz processor, 128MB RAM and 10MB free disk space on your hard drive. A sound card, speakers and microphone are required (see below) and of course an internet connection (33.6Kbps minimum dial-up minimum). In order to take advantage of all of the advanced features of Skype and to experience the best sound quality possible, the following configuration is highly recommended: a 1GHz processor, 256MB RAM and 30MB free space on your hard drive. A full duplex 12  Silicon Chip You’ll be asked to give a Skype Name and a password when you log in. sound card is also better (most sound cards made after 1998 are full duplex) and a headset (earphone/microphone) A broadband internet connection will not only get the most from Skype but will also save you dial-up charges. A PC headset is desirable if you want lowest background noise (or privacy!). These are readily available at electronics and computer retailers and shouldn’t cost you much more than twenty dollars or so. The alternative to a headset or speaker/mic is to use a netphone, as we have shown earlier in this feature. The one we used simply plugs into the USB port and is ready to go immediately. Skype works behind most firewalls and gateways without causing new security risks. Skype calls are encrypted for your security, something the vast majority of public network telephone calls cannot claim. Contact list Your contact list will naturally be empty when you start Skype for the first time. You can search for other Skypers from the worldwide Skype users list or you can enter a Skype user directly (eg, if they’ve emailed you with their skype name). Calling another Skyper You can either right-click or doubleclick a name in the contacts list or You can search the world-wide Skype user list for your friends and colleagues and authorize them to see when you’re on line. Or you can put in some parameter to search for (age, sex, language, location, etc) to find someone really interesting to talk to. 21st century penpals, perhaps? siliconchip.com.au ant Skype and Skypeout! – you can continue using it as you normally would while on line. In fact, you can even IM (instant message) a Skype user while you are talking to them if you want to share files, transfer inform ation, etc. Or you can use Skype itself to transfer files up to 2MB – while on a call! We understand even webcams and webcam software will still work while Skyping but system resources might come into play if your machine is towards the lower end of the range. Skype is in its infancy – it is currently V1.0 (until July 27th last it was in beta format!). More features have been promised in future releases. Calling a “real” phone is done using “SkypeOut”, another feature of Skype. Just a reminder (and SkypeOut will also remind you as you make the call) this is not free. But to most countries, including Australian numbers, it’s either significantly cheaper or dramatically cheaper to SkypeOut than to call on the phone. Remember too that calls are timed (to the minute). So talking to someone overseas for hours might not cost you an arm and a leg (as it would on the phone) but it will cost a finger or toe! SkypeOut calls to mobile numbers in many countries are just as cheap as calling fixed phones but SkypeOut calls to Australian mobiles will cost you about 28c per minute (as at August 1). As SkypeOut is European, calls are costed in Euros ($) and you have to convert them back to Aussie dollars. If you have a very short message to give someone locally on the phone (eg, a couple of minutes or so) it will even pay you to SkypeOut them rather than ring them. The minimum local call these days is about 15c – you can get five minutes of SkypeOut for that! Before you can call to fixed or mobile phones you need to establish a credit in your SkypeOut account. You do this by adding Euros to it via your credit card. If you don’t have a credit card then you can’t use SkypeOut (maybe it’s about time to get into the 21st century?). The choices are $10, $25 and $50 – roughly equivalent (Aug 1) to $AU17, $AU43 and $AU86. You have 180 days to use any balance remaining. Once you have a credit balance, you can call any number, anywhere. Use the same international dialling standards as you would for any “normal” international call: if you’re ringing a number in London, England, you’d dial +441(number). Of course, there’s no need for an international dialing prefix (0011 or whatever) – with SkypeOut you’re already in the international realm! Likewise, if you’re calling a number in Sydney, Australia – let’s say SILICON CHIP, you’d dial +61299795644, even if you are situated right next door. (The leading zero in the area code is always dropped in international dialling). And if you’re calling an Australian mobile (say 0404 999999), same rules apply: you dial +61404999999. If you forget that leading +, Skypeout will prompt you to put it in. There you have it. The very low-cost way to get very low-cost international, long distance, mobile and even local calls. If you get into trouble, SkypeOut has a very detailed help file along with FAQs, which should answer most of SC your queries. To make calls to fixed or mobile phones, you buy credits on-line (it’s a secure site) . . . . . . and you can check your account balance at any time. So far I’ve used Q0.03 (about 5c!) to make calls. Calling a standard phone Poor old Clem’s got only one friend... or maybe he hasn’t got around to putting them in his contacts list yet! search window to initiate a call. Note that Skype allows you to block calls as well, so if you’ve been a bad, bad boy (or girl) and someone has placed you on their blocked list, you’re out of luck. Answering a Skype call You’ll hear a phone ringing (surprise, surprise) and it’s up to you whether you answer or not. As soon as you accept the call, you can start talking. Either party can “hang up” or terminate the call at any time. Conference Skyping You can have a conference call of up to five people with Skype – again, all totally free if they are using Skype. You do this by holding down the control key and selecting the participants from your contacts list. When those contacts answer their Skype call, they immediately join the conference. You can also add another Skyper to join an existing call (conference or normal) by “inviting them to conference” (up to the five limit). If you are planning a conference call, get the person with the best internet connection to be the conference controller (ie, initiate the calls). Using your PC while Skyping Skype does not take over your PC siliconchip.com.au September 2004  13