Hello again. It's good to be back with The Javea Grapevine after an absence of almost a year. For those of you who haven't a clue who I am, I'm a (theoretically!) retired Computer Technician come Information Technology teacher in the Adult Education sector. I give classes called, as is this column, "Computing for the Bewildered" at The Oasis Centre in Javea, which will be restarting in September / October. I will give you full details of these in my August and September articles. My last article for The Grapevine was in June 2002, and was on the then new phenomenon of ADSL. In the intervening months, ADSL has matured and is now available throughout almost all of the area covered by The Grapevine. It is one of the things I'm asked about most often, both by e-mail and in my classes, so I thought I'd go through what it is, what it can do and how you can get it. ADSL stands for Asymmetric Digital Subscriber Line, which probably means nothing to you, so let's keep it simple. If you have ADSL, your Internet connection is completely independent of your telephone, even though both come into the house through the same socket. You will have a permanent (all the time your computer is on) connection to the Internet at a maximum speed (normally and nominally) of 256kbs for incoming data and 128kbs for outgoing. The speed difference is the Asymmetric part of ADSL, and is of no real life importance since almost everybody downloads far more from the Internet than they ever upload. ADSL is set to transform Internet connections - it is (comparatively) cheap, with a flat rate fee, always available and, generally, much faster than what has been available previously. Telefonica have steadily been making their network ADSL capable. Applications are being dealt with within a short time frame, often less than a week from the initial application to the service being up and running. There is a web site (links at the end) where you can check the availability of ADSL for your own number, but an even better way, if you want it, is to contact an ISP and ask them. The major Spanish Internet Service Providers (including Telefonica themselves) are competing vigorously for ADSL customers, with the result that there are some really good deals around. If you want the standard 256kbs/128kbs connection, and you're prepared to do your own installation, then the extra hardware needed will be provided free of charge. My own ADSL contract is with Telefonica. Since the physical wire into my house is still their responsibility irrespective of who my ADSL ISP is, I reckon that if something goes wrong I'm in a good position as one party won't be able to blame the other! Therefore, the details I'm giving are for my connection through Telefonica. I have had my connection for just over a year. In that time it has been down (unavailable) for no more than fifteen minutes in total. A first class record. Prices seem to have stabilised at roughly 40 Euros a month for a standard, full time connection. Wanadoo have a slightly cheaper option which is not turned on between 0800 and 1500 Monday to Friday. I was given a router, some microfilters which enable me to use my voice phone while I'm on line, a network card to fit inside my computer, all the cables and some installation software. This all arrived by courier. Nowadays, most people are given what's (wrongly but understandably) called an ADSL "modem" which is plugged into the computer's USB port. Although this has a few disadvantages and is less flexible, it's undoubtedly easier to install and run than a full-blown router + network system, and is all that most people (including, probably, you, the reader), need. In any case, if you don't think you can manage it, Telefonica (or Terra or Wanadoo) will arrange for somebody to visit your house and install it for about 90EUR. It all sounds wonderful, doesn't it! Surely, you must be thinking to yourself, there must be some drawbacks. Yes, you're right, there are three that I can think of. Firstly, you can't have more than one ADSL connection. Unlike a dial-up or RDSI, you can't use your "spare" account if your main one fails for any reason. Also, if you move house, you will need to start all over again in your new one. You can't take your ADSL account with you and neither, I'm given to understand, can the new user of your phone take over your existing account. The second drawback is that the minimum contract is for 1 or in some cases 2 years. Even if you don't use the service, you'll still have to pay the monthly fee, and if you're not happy, you can't simply change providers. The third drawback is one that the ISPs are playing down, and which to be fair hasn't yet become an issue, but could become so as ADSL becomes even more popular. The problem is that of contention. When you connect by a dial-up or RDSI connection, the wire between your house and the ISP is for your exclusive use. There may be congestion from there forwards, but nobody else shares your phone line. With ADSL this isn't the case. Think of your mains water supply. Normally, the pressure at your house is reasonable, but if everybody in your area turns their taps on at the same time the pressure will drop. That is contention. You are contending with others in your area for the available capacity of the water main. So it is with ADSL. Each 256kbs/128kbs line can be shared with others. For BT, the contention ratio is declared to be a maximum of 50 to 1. In other words, if you were all downloading at the same time, you would be sharing the 256kbs connection with up to 49 others. Naturally, the system knows which computer to send which data to, but the speed drops - as low as 5kbs in theory. Telefonica, Wanadoo and Terra haven't (as far as I know) declared a contention ratio. Instead, they have guaranteed a minimum throughput of just 10% of the theoretical maximum, in other words 25.6kbs or, if you prefer, just over 3 kilobytes per second, or even less than you can get through a dial-up. This is much less impressive than the figure of 256kbs which is the theoretical maximum. Once again, however, I must emphasise that the misgivings I had a year ago haven't materialised; I'm still getting roughly 90% of the theoretical maximum as long as my source can keep up! There are various facilities available over the Internet that become possibilities with ADSL, but which require too much bandwidth for dial-up connections. I'll talk about those next time. If you want to know more about ADSL, including the various ISPs offers, there's a page on one of my websites: http://costablancaexpats.net/adsl/adsl.html with links to other sites which go into the topic in great detail, including a site where you can input your own number and see if ADSL is available to you. If you have been, thanks for reading this.