ISDN versus ADSL - the consumer choice

It appears that homeworkers will soon be spoilt for choice regarding high-speed network access, with ADSL (asymmetric digital subscriber line) just around the corner and BT cutting the fees for its traditionally pricey ISDN services.

However, the two services are by their very nature suited to different tasks and users need to look at the type of work they do at home before plumping for one or the other.

"ADSL is very good at providing permanent connections to a service provider, which might be an internet service provider. But anything where the call passes through the switch fabric is going to be more expensive," explained a BT spokesman.

"If a homeworker's employer wants to extend the corporate intranet out to the local exchanges and provide the homeworker with ADSL to connect to its corporate intranet, then that'll be a very useful thing to do. If on the other hand, homeworkers happen to be doing voiceovers and want to talk to radio production companies up and down the country, then they'll need ISDN," he added.

But Neil Spencer-Jones, managing consultant for NCC Services, the trading company of the National Computer Centre, believes that, for the moment at least, ISDN is generally more useful to home workers.

"I would see ADSL very much as an access technology for the internet specifically," he said. "While you can use ISDN for that too, you can also use it to dial back into your central office. If you are going to use ADSL for homeworking, you have to take a different approach to networking, maybe using the internet as your network."

The realities of ADSL
Although enthusiastic about ADSL, Spencer-Jones believes users should be realistic about what the technology can do. "If you want to be committed to homeworking, you have to look at using web-based systems using 56k lines. Whether you are using ISDN or ADSL, you still have to have systems that operate across a low-bandwidth connectivity," he said.

"The homeworker is going to be competing with the teenager who is watching Sky Digital or interactive TV and someone else will be doing shopping, so you are not going to be able to get a 500k ADSL link dedicated to the homeworker. And then maybe both partners are homeworkers and you're not going to get an ADSL line each."

Despite this, it is ADSL rather than ISDN that will really bring about the next technological revolution for home users by making such offerings as video-on-demand available for the first time.

The BT spokesman said: "Video-on-demand is one of the classic applications for ADSL because two or two and a bit megabits per second is perfectly adequate for broadcast quality."

So it would appear that ISDN is a better option if users want to dial into their corporate server remotely or if they want to send pictures and documents to colleagues over the wire because it provides a guaranteed connection.

On the downside, however, ISDN is significantly slower than ADSL, offering connection speeds of only 128kbps.

ADSL, on the other hand, is better if customers want an 'always on' connection for web browsing, accessing corporate intranets or using streaming media.

The service that BT plans to introduce for business users from the end of this month will offer connection speeds of up to 2Mbps, which is 16 times faster than ISDN, although its consumer service, which will be available at the start of September, will be a mere four times faster at 500kbps.

On the downside, however, users cannot use ADSL to dial directly into their corporate servers.

Falling prices
Meanwhile, BT is being forced by regulators to open up its local telephone network to enable other companies to offer services such as ISDN and ASDL as well - and the increase in competition could well bring down prices.

But while ASDL is now due to appear more than a year later than promised, Eric Owen, telecoms services specialist at analyst IDC, argues that it is not in BT's interest to move any faster.

"The problem is that ADSL is really tied to unbundling the local loop. If BT too rapidly deployed ADSL nationwide, it would have to allow its competitors access to that facility also. Whereas ISDN is available nationwide and BT already has an attractive ISDN option for home users, it doesn't want to cannibalise its existing ISDN revenues by rolling out ADSL," explained Owen.

"I believe BT has agreed to unbundle the local loop by this time next year. That may happen quicker depending on the concessions BT wins back from the government," he added.

Such concessions could include lifting the ban on BT broadcasting across its telephone network.

But Spencer-Jones sounds a note of warning. "BT-knocking has become a national sport in the UK, but in reality you wonder, when these things are opened up, whether any of the other operators will come and offer any of these things. A lot of the cable companies haven't really offered free internet access, for instance, which they are able to do," he said.

Spencer-Jones also believes that while competition may occur in the major urban centres, consumers living in areas with a smaller population are unlikely to have the same range of choices.

"It worries me as an independent that we might see the BT portfolio get cherry-picked. Then people in those regions end up with services which BT may even want to charge a higher amount for, because the highly profitable areas have been cherry-picked by somebody else. This means that BT gets left with the less profitable part of the portfolio," he said.

And this could lead to technology gaps based purely on where someone lives. "We've heard stories that 70 to 80 per cent of the UK will be covered. But I think that will be 70 to 80 per cent of the population, not the UK geographically. In geographic terms, it may be as low as 10 to 15 per cent," he added.