Network: Wanted: an Internet without speed limits

Even with the fastest modem, accessing Web pages often involves a lengthy wait. Yet the technology to speed up the information superhighway is in use in the US. In Britain, you will have to be patient. Cliff Joseph reports.

This time last year we were all eagerly waiting for the new generation of 56K modems to arrive. We were looking forward to faster Internet access and fewer of those thumb-twiddling waits while we downloaded adverts that we didn't want to see in the first place. But 56K modems have proved to be something of a disappointment. They are faster than the earlier 33.6K and 28.8K models, but the speed difference isn't really great enough to change the way people use the Internet.

Current modem technology, which is based on Pots (plain old telephone service), seems to have reached the end of the line. If the Net is going to become a true mass medium it needs a new technology that provides much faster access.

There are a number of competing systems undergoing trials both here and in the US. Unfortunately, progress in the UK seems to be slow. The three main competitors at the moment are ISDN, cable and ADSL.

ISDN (integrated services digital network) isn't new at all, and has been in use for several years in the US and Europe. When you have ISDN installed, you get two new digital telephone lines that can each provide a connection speed of 64K per second. That is just under twice the speed of a standard 33.6K modem. But when you connect to the Internet you can use both lines together, for a combined speed of 128K per second. You also have the option of using one line for the Internet while simultaneously using the other line for normal calls.

"That's more than adequate for high-speed Internet access," says BT's Simon Gordon. That may be true, but the problem with ISDN is that it is very expensive. BT charges pounds 230 to have the lines installed. Line rental is at least pounds 150 a quarter, with call charges added on to that, although the line rental does include a certain amount of free call time. These high charges put ISDN out of the reach of ordinary Internet users. ISDN is primarily used by companies that need high-speed data links to their clients or between offices. BT is about to start a trial with a mass-market ISDN service that it calls Home Highway, but it hasn't decided on pricing for the service.

Meanwhile, in the US, most of the focus is now on cable and ADSL, both of which are significantly faster than ISDN.

"We're backing both technologies," says Mike Valiant of 3Com, one of the world's biggest modem manufacturers. "But it will be interesting to see how things develop in the UK."

Cable connections can handle data transfer rates of 27-34 megabits per second, but the speeds you get in practice will be much lower. Cable systems link groups of users together into "channels" consisting of up to 500 separate households, so you have to share your connection with others on your channel. Even so, you should be able to reach speeds of 2Mbps, even at peak times.

Unfortunately, you can't subscribe to cable tomorrow and get a 2Mbps Internet connection straight away. Cable companies have to upgrade their exchanges to provide this service, and British companies have been slow to do this. 3Com already sells cable modems in the US, "but the stage we're at in the UK is just talking to cable companies", Valiant says. "We hope to see services in mid-'98."

The other problem with cable is that not many people use it. Most of the world still uses old-fashioned Pots telephone lines. Any new modem technology that hopes to achieve mass-market success needs to work with those telephone lines. That is where ADSL comes in.

ADSL (asymmetric digital subscriber line) is just one version of a technology that is generally referred to as DSL, but most of the development work in this area is concentrating on this version. It is available from a number of regional telephone companies and Internet service providers in Canada and the US. Next month, both Microsoft and Intel are expected to announce their support for ADSL.

ADSL modems can provide similar download speeds to cable modems, but they work with standard copper telephone lines. They achieve higher speeds by sending data along frequency bands that can't be used by ordinary modems. The "asymmetric" feature of ADSL refers to the fact that upload speeds - sending data from the user back to the Internet - are slower than downloads. Even so, the upload speed is still about 200Kbps.

The odd thing about ADSL is that its speed depends on your distance from the local telephone exchange. Peak speeds, within a few hundred feet of the exchange, can be as high as 9Mbps, but the average speed for most users will be 1.5-2Mbps.

BT has been conducting trials with ADSL since 1994, and says that it can sustain download speeds of 2Mbps at up to four kilometres from the exchange. That distance covers more than 70 per cent of BT users, so it has mass-market potential. But if BT has been testing ADSL since 1994, you might well wonder why it is available in Canada and the US, but not here in the UK.

Another ADSL trial is about to start in west London, but the main problems now are financial rather than technical. "BT has done numerous trials," argues 3Com's Valiant. "They know the technology works - they're just not sure how to pay for it."

Like many other telecoms companies, BT initially saw ADSL as a way of delivering video on demand to people's televisions, rather than using it to connect their computers to the Internet. However, while companies in the United States and Canada are focusing their ADSL efforts on the Internet, BT is still concentrating on video on demand and other services.

"We don't see ADSL replacing ISDN," says BT's Simon Gordon. "The main application will be interactive services such as banking or shopping. You're not going to use it for the Internet alone."

However, Valiant believes video on demand will not provide BT with the money it needs to upgrade its exchanges to provide ADSL. That leaves ADSL in a kind of marketing limbo while BT decides how to go about selling it. Given that BT has yet to set a price scheme for its mass-market ISDN service, you should not hold out much hope for ADSL in the near future.

Internet companies such as the London-based Direct Connection agree that BT is slow to adopt these new technologies. "I would like to see them moving more quickly," says Ben Knox, director of Direct Connection. He acknowledges that ISDN is well-tried and reliable, but suggests that BT could provide ADSL as a premium option for those users that want it.

Knox and Valiant agree that ISDN could be a useful interim solution until ADSL is introduced. It is disappointing, though, to think that promising technologies such as ADSL are being held back not because of technical difficulties, but simply because British telecommunications companies cannot figure out what to do with them.