Laurence Blackall on the prospects of a technology that could cut Net users' phone bills
They call it the World Wide Wait. That time you are sat in front of your PC waiting to download fancy graphics from the Internet. Doing nothing except paying your telephone company. And knowing that, with an ordinary phone connection at least, things are unlikely to get much better.

But help is at hand in the form of the Integrated Services Digital Network. ISDN enables connections at more than twice the speed of the fastest modem, but requires a special line and dedicated kit at the subscriber's end. The installation of the line will cost pounds 400 (plus VAT) from BT and a quarterly rental of pounds 84. And the terminal adaptor (what you use instead of a modem with ISDN lines) will cost you more than twice as much as an average 28.8 kbps modem.

Net users in France and Germany get a much better deal. France Telecom charges 200 francs (pounds 25.50) a month for an ISDN line, but no fee for converting your line. In Germany, it's even cheaper, at DM44 (pounds 19) a month. BT gets twitchy when defending its pricing, which seems to be based on the fact that it can sell all the ISDN connections it has time to install, so why cut the price? And anyway, ISDN is not a residential service.

BT says its call charges are lower than those in France or Germany, but that does little to quell complaints about the pounds 400 installation. The good news is that BT has allowed other companies to bundle ISDN installation with a terminal adaptor at a "special" price.

Deutsche Telekom is heavily subsidising ISDN terminal adaptors and reducing monthly rental charges in an effort to sell ISDN lines. And with over 2.8 million basic ISDN channels sold, it is by far the world's largest provider. Why doesn't BT do the same? Possibly because it thinks the future of ISDN is not sufficiently secure to merit the investment. One only has to look at its Interactive TV trial which is using a technology called ADSL which stands for Asymmetric Digital Subscriber Line. This is a (fairly) new, super high-speed modem technology which provides data services, such as Net access, over the existing telephone lines. The attraction of delivering superhighway over the current network of B-roads must be irresistible to BT.

So how fast is ADSL? And why is it Asymmetric? Well, it is asymmetric because it goes faster in one direction than the other, and it provides a "downstream" data transfer rate at a speed of at least 1.5Mbps, more than 20 times faster than ISDN. The upstream channel speed varies from 64kbps to 640kbps.

The rub is that ADSL is not here yet. US vendors are talking about an ADSL modem aimed at home user selling for a bit under $1,000. But don't hold your breath. If you want even a half-decent speed of connection, ISDN is the only game in town.