ADSL - Reputations on the

A new style of modem technology - ADSL - is gathering momentum. Driven by demand for high-speed internet access, teleworking and video conferencing, will ADSL be the death of ISDN?

After years of marketing neglect, BT has finally woken up to theDriven by demand for high-speed internet access, teleworking and video conferencing, will ADSL be the death of ISDN? potential of using its existing network for data transmission.

Six months after the same phenomenon was recognised in the US, Bill Cockburn, BT group managing director for the UK, finally concedes: 'There is more data transmitted over BT's telephone network in the UK than voice calls.'

One consequence is that the telecommunications giant has repackaged its entry-level digital telephone service into two offerings: Home Highway and Business Highway. These are essentially basic-rate ISDN services (launched more than 10 years ago) with a few added frills.

But is this all too little, too late? Should resellers be taking advantage of the buzz BT has created around Highway, or should they stand on the sidelines and see how quickly Asymmetric Digital Subscriber Line (ADSL) - capable of speeds which leave ISDN trailing - is launched and adopted by SME, SoHo and domestic users?

One key supplier that is poised to take advantage whichever way the modem market blows is Hayes Microcomputer Products. Hayes - currently seeking protection from its creditors under US Chapter 11 laws for the second time in its history - shipped its first ISDN product as long ago as 1985.

The company already has an ADSL product going out through distribution in the US.

The ADSL product in question is a PCI bus card developed in conjunction with Alcatel, whose input was to provide the necessary central site equipment for any ADSL style of connection.

PC Dealer spoke to Bill Pechey, former chief engineering officer at Hayes until he left the company earlier this month. Pechey believes Hayes will put its ADSL offering through UK distribution 'as soon as it makes sense'. The catch is that there is only one vendor actively trialling ADSL in the UK - namely BT.

'It will be some time before resellers start selling ADSL here,' he predicts.

In fact, BT was the first European operator to join the Universal ADSL Working Group (UAWG), which is behind standards for DSL Lite. This is a version of ADSL that will work up to 30 times faster than the latest modems, but which can also operate over existing copper telephone lines.

Other members of the group include Microsoft, Compaq and Intel.

ADSL trials with UK ISPs were first announced by BT in September 1997.

At that time, BT's ADSL technology was supplied by a consortium led by Alcatel and Fujitsu.

Last month, BT announced what it called its first Interactive Services Network (ISN) trial in London. Designed to run until March 1999, the trial uses ADSL technology supplied by Westell, in addition to that from Alcatel and Fujitsu. Westell is a US manufacturer with headquarters in Aurora, Illinois, and already possesses experience with ADSL and HDSL (an ADSL variant) systems.

In terms of speed, BT's ISN offers downstream (to the subscriber) at rates of up to 2Mbit/s, while information can be sent back (by the subscriber) at speeds up to 256Kbit/s. ISPs that have already signed up for the ISN trial include BT Interactive, I-way and Virgin Net. Additionally, Video Networks (VideoNet), a video-on-demand interactive TV and home shopping services provider, has also signed up for the trial.

Bill Pechey suggests that the typical ADSL subscriber will 'use the BT provided service as a (data) pipe'. He anticipates that BT's ADSL charges will take the form of a fixed fee - so effectively will be akin to having a leased line to the internet. 'Lots of people would very much like to have that,' Pechey adds.

But ADSL's asymmetric nature complicates matters. 'It's no good for a heavy-duty web server,' Pechey points out, 'because a private ADSL site would only be able to offer its viewers a 256Kbit/s feed. But, on the other hand, it's not bad as a reasonable low-cost Website since it is more flexible than just uploading pages to somebody else's Website.'

Pechey doesn't think that selling ADSL will require any special skills.

'Any reseller who knows about IP can sell it. It'll be cheaper than a 64Kbit/s leased line and good value,' he says.

Video conferencing is an obvious application for ADSL. There are suitable standards already in place - such as H.323 - and Microsoft's NetMeeting software is rapidly establishing itself as the de facto industry standard.

'It's not broadcast quality, but it will still be very good quality,' Pechey claims.

He points out that ADSL's upstream 256Kbit/s channel is more than enough for one set of participants to transmit a video picture of themselves to a central site, while the 2Mbit/s downstream channel will be more than sufficient to view a high-quality video image of all the other participants in the video conference. BT maintains that other uses for ADSL will include video on demand, home shopping and banking.

Steve Robertson, BT's data products director, says: 'With the success of ISDN and the launch of BT Highway, ISN offers a natural evolution to the next generation of communications. It demonstrates the kind of technology we can expect by the year 2000 in our homes and businesses. Ultimately, the services offered on the ISN trial will be part of the BT Highway family of digital access systems.'

Some, however, remain unconvinced about the impact of ADSL in the short term. Nick Hunn, technical director at TDK Grey Cell, says: 'We are looking at ADSL and we are also tracking how the demand for G.Lite goes.' G.Lite is another variant of ADSL championed by Rockwell.

'The worry is that there will be a proprietary implementation of ADSL in each country,' Hunn continues.

'For example, Deutsche Telekom in Germany is allied to Ericsson's ANX offering.' As a result, Europe could be covered by pockets of isolated ADSL systems rather than one universal system.

Another thorny issue is user demand. 'The question is how big the European market for ADSL is going to be,' Hunn says. 'Early widespread adoption of ADSL doesn't seem likely. Europe has had a decent digital telephone network for some time, whereas in North America, the digital telephone network has been poor. Essentially, technologies such as ADSL are a bodge to get around America's existing network's shortcomings.'

Another important point which Hunn makes is the fact that with standard ISDN offerings, including Home Highway, the subscriber can achieve 128Kbit/s data throughput speeds in both directions. Hence ADSL's current 250Kbit/s upstream channel isn't that much faster since it's only twice as fast as ISDN.

Hunn also believes that ADSL is currently a technology looking for that Holy Grail of IT - the killer app. 'In ADSL's case it's video on demand, perhaps,' he suggests.

On a more positive note, James Dunn, technical director with ATM specialist integrators K-Net, says: 'ADSL offers a brighter future than ISDN. But with the limited number of trials taking place, it still looks too far away to be worth waiting for. I would advise customers to go with ISDN and look to migrate to ADSL in the future.'

One benefit for resellers mentioned by K-Net is the fact that ISDN and ADSL should share the same cabling infrastructure - so there should be no issues regarding migration by the user. But how does ATM, with the potential to offer much higher data throughput speeds than ADSL, fit into the scheme of things?

'ATM fits extremely well into the ADSL programme and it is an area undergoing much work within the ATM Forum,' says Dunn. Furthermore, as ADSL can carry both ATM and analogue telephone (POTS) traffic, it removes the need for operators such as BT to support costly separate networks for both data and voice.

'K-Net firmly believes that any technology which allows faster communications at a lower cost must be beneficial,' Dunn says. 'We feel that ADSL will bring real gains, particularly in the field of teleworking where ISDN is simply running out of steam, and in video conferencing where ISDN's 128Kbit/s simply is not adequate for any form of telepresence.'

As far as reseller opportunities go, Simon Brooks, manager of BT's ISN trial, is naturally very cagey. 'BT will be looking into reseller opportunities nearer to the completion of the trial.'

However, the buzz BT is creating with Highway, combined with the hype surrounding ADSL in the US, are certainly stimulating user interest - particularly for teleworking and video conferencing applications, as well as the more predictable demand for high-speed internet access.

In 12 months, ADSL could well be a serious alternative, but for now the window of opportunity appears to be with the tried and tested technology offered by ISDN.

WHAT IS ADSL?

Asymmetric Digital Subscriber Line (ADSL) is a technique which is completely independent of existing modem developments. In effect, ADSL grew out of research into delivering video over cable TV networks. There are other variants of the same technology, such as Synchronous Digital Subscriber Line (SDSL), which have applications in areas other than straight modem replacement.

The most significant aspect of ADSL is that, like V.90 and Prestel before it, it involves two channels operating at different data throughput speeds (hence it is asymmetric). The down channel, which delivers data to the subscriber, is the fastest, operating in the region of 2Mbit/s to 8Mbit/s.

This works out as roughly between 30 and 50 times faster than current V.90 modems. (The difficulty here is that V.90 modems don't actually yet deliver the 56Kbit/s performance which their makers promise. It is closer to 44-46Kbit/s).

There are two ways in which ADSL could possibly be delivered. One is to provide the subscriber with a completely updated style of telephone wall socket, as is currently the case with ISDN and BT Highway. The alternative is to deliver ADSL via a standard telephone socket. This is the reason why groups such as the UAWG are working together to formulate an ADSL standard which might stand a chance of being universally accepted.

While BT has standardised so far on 256Kbit/s and 2Mbit/s, the Hayes card is actually capable of 640Kbit/s and 8Mbit/s.

There is, however, a big difference between the US and European markets.

US telephone companies effectively deliver just a bare pair of wires to their consumers - it is up to the customer to purchase all the necessary telecommunications equipment.

In Europe, the telephone company provides the wall socket, as well as other additional equipment needed, such as routers in many cases. Consequently, ADSL - and, for that matter, ISDN - offers much bigger opportunities to resellers in terms of hardware sales in the American market than it ever will within the UK.

THE FUTURE FOR ADSL

There will be 2.5 million ADSL lines in the US by 2001.

Source: International Data Corporation, 20 January, 1998

xDSL will have 10 per cent of the US remote access market by 2002.

Source: Gartner Group, 13 March, 1998

By the year 2002, 5.5 million European households will be served by xDSL lines.

Source: Datamonitor, 11 April, 1998

xDSL installations for business use (worldwide) will reach 711,700 by 2001 and 5,152,200 by the year 2006. By 2006, 73 per cent of business installations are expected in the Asia/Pacific Rim region. Only about 17 per cent will be in the US and seven per cent will be in Europe.

Source: Communication Industry Researchers

PITCHING ADSL

Cost - The consensus is that prices will have to drop considerably to be attractive to a large audience - possible within the next two to three years. If that happens, ADSL will be competitive with alternative technologies, but more expensive than low-speed network access. The advantage of ADSL resides in value added rather than reduced costs.

Time - Users save time from faster downloads and 'always on' connectivity.

The former is important for large file transfers, although this may not comprise a significant proportion of online activity for many users. The latter saves a few minutes a few times a day. Messages arrive in real time.

Quality - The technical quality of connectivity is substantially increased because of high-speed access, which reduces wait times and enables applications such as video conferencing. Service providers in this sector have a long history of providing a high reliability, high-quality network service.

Access - ADSL provides worker access to corporate LANs and WANs and expands the customer reach for small and large businesses alike. Irregular access to ADSL service because of network limitations and/or inability to pay could raise customer satisfaction and regulatory problems as the service becomes more widespread.