ISDN Comes of Age

If you thought that modem on your desk was fast , hold on to your hats

by Simson L. Garfinkel

Remember when punk rock and 1200-baud modems were hot? The Hayes Smart modem could move data four times faster than most other modems then on the market. But these days, high-speed modems let users pump 19,200 – or more – bits per second over ordinary telephone lines using a variety of signal-processing and data-compression techniques.

Fast forward ten years: Punk rock is still dead and modems are faster still. But who uses modems anymore? By the turn of the century, anyone who is serious about data communications is "jacking in" – connecting their computer directly to the phone company's digital network and moving data at megabits (Mbits) per second.

Sound like cyberpunk? It's not. It's a new system for digital communications called ISDN.

And it's here today, initially offering speeds of 128Kbits per second for less than $400, if you have a NeXT.

Innovative Standards Doing Nothing
For years, ISDN has been a pie-in-the-sky future for telecommunications junkies. The acronym, which stands for Integrated Services Digital Network, promised a direct digital interface between the telephone company's central office and the customer. ISDN was to do the same thing for telephones that compact discs did for music: By sending sound to the customer as a digitized stream, ISDN would simultaneously improve the phone system's quality and open up the world of data communications, just as compact discs made CD-ROM possible.

But ISDN has been slow – some say painfully slow – in coming to the U.S. telecommunications market.

Until now, the biggest ISDN users have been telemarketing companies. These firms benefit from ISDN's dramatically faster "call setup time" – which enables operators to make more calls per hour, boosting profits. And while state public utility commissions across the country argue about the merits of Caller-ID, a proposed system that would display the telephone number of an incoming phone call, ISDN subscribers have been quietly enjoying this benefit (renamed ANI, for Automatic Number Identification) for half a decade. Many firms that sell merchandise by telephone use ISDN to get the caller's phone number to automatically pull up customer records.

In all of these cases, however, ISDN was available only under special arrangement, usually in blocks of dozens, or hundreds, of lines. And the few companies that actually had ISDN couldn't use it to place a digital phone call from one telephone exchange to another, because the interconnection software, which depended on a new phone system standard, didn't work properly.

"The fact of the matter is there are about five different versions of ISDN in existence today, with very limited deployment and very limited use," says Dick Aloia, assistant vice-president of network access technology for Bellcore, the R&D arm of the nation's regional telephone companies.

All of that is now changing, and NeXT – the only computer company whose every machine comes equipped with a Digital Signal Processor (DSP) – is uniquely poised to take advantage.

Interesting Services, Dream Network
Two years ago, NeXT's communications gurus were trying to figure out ways to tap into the computing-at-home market.

"We were sitting in a meeting and Steve Jobs said,'Go out and make IP [Internet Protocol] run over phone lines as fast as possible – and I want it to run over ISDN,' " recalls Tim Kreps, NeXT's developer advocate for networking and communications.

IP is the network standard that NeXT and other UNIX workstations use to communicate over Ethernet. Running IP over ISDN would mean that a person with a NeXT- station at home could access electronic mail, files, and applications at work – doing it quickly and transparently.

The obvious way to make IP run over ISDN was to use the DSP. Ever since NeXT introduced the Cube, engineers both inside and outside the company dreamed of programming the DSP to emulate modems, fax machines, telephone dialers, and voice-mail systems. One engineer even rigged up a demo in which a NeXTcube automatically faxed e-mail to a person out of the office. The time had come to take the best elements of those demos and turn them into a product.

A year later, the group was just finishing off a prototype that was code-named "Babblefish" (the name of the universal translator in The Hitchhiker's Guide to the Galaxy). The box, now being manufactured by Hayes, can connect any NeXT to either a conventional or an ISDN telephone line.

Connecting the box to a regular telephone line produces an answering machine on steroids. It lets you use a NeXT to place and receive telephone calls, generate and decode touch-tone signals, and play and record voice over the phone line. In addition to answering machines and voice mail, developers will be able to use the box to create new information services delivered over regular phone lines to ordinary touch-tone telephones.

But the real benefit comes when you connect the box, now called the Hayes ISDN eXTender, to a digital phone line: It provides a full digital interface to the outside world, capable of transferring data at rates of either 64Kbits/sec or 128Kbits/sec. That's almost 6.8 times faster than today's fastest modems – and 3.4 times faster than the maximum possible throughput of the NeXT serial ports (which are limited to a maximum speed of 38,400 baud). And, true to Jobs's wishes, it will run IP.

The ISDN eXTender is a small box containing an ISDN chip set, for connecting to ISDN lines, and an analog-to-digital, digital-to-analog converter, for connecting to conventional telephone lines. The box has no memory, no CPU, and draws its power directly from the NeXT. Its sole purpose is to bring the signals on the telephone line to the NeXT's DSP. The rest is done by software.

Because the Hayes box has little intelligence, it's cheap: With a suggested retail price of $349, it costs about $1000 less than other ISDN interfaces. (Hayes's other ISDN interface, the Hayes ISDN System Adapter, lists at $1595, largely because it needs to have its own DSP, software, high-speed computer interface, and power supply.) It needs PhoneKit and ISDN-Kit, both standard with NeXTstep Release 3.0, to run.

"We will have some kind of simple configuration application for setting it up," says Kevin Wells, NeXT's manager of software products. Users will have to get an Internet address assigned for their com- puter. After that, "it will be one button [to push] for the base case."

I See Dollars Now
But what will NeXT users actually do with ISDN? That depends on what they're doing now.

"ISDN won't let you do anything that you can't do already," says Joe Gustafson, ISDN market planning director for NYNEX, the parent of several Bell operating companies. But in many cases, he adds, it will dramatically lower the cost of high-speed communications.

For example, today it is possible to get a 56Kbits/sec leased line from the phone company between your home and your office. The cost can be up to $1000 to install and $200 to $300 per month to maintain. Compare that, for example, with an ISDN installation fee of $15 and a monthly fee of $8 (in addition to the cost of a standard telephone line) – the tariff just approved for Massachusetts by that state's Department of Public Utilities. In California, the monthly cost of an ISDN line is less than $30.

Long-distance ISDN calls will cost the same as current long-distance voice calls; companies like MCI and Sprint already have fully digital networks.

Once National ISDN 1 is in place (see sidebar "What's the 'D' stand for?"), the long-distance networks won't even know the difference between a voice call and a data call.

These dramatically lower costs will open up ISDN for small- and medium-size companies – especially those with branches in different cities. For example, a graphic arts firm with offices in Houston, Chicago, Boston, and San Francisco might use ISDN to transmit digitized images instead of sending slides by Federal Express. With a NeXT at each end, a 26MB image could be transferred coast-to-coast in less than four minutes, and for less than a dollar.

NeXT's other big ISDN market is likely to be people working at home. "With ISDN, you're really on-line," says Eric Bergerson, managing director of Objective Technologies, a New York–based NeXT developer.

With ISDN, says Bergerson, NeXT users will be able to transparently access their files and applications over the telephone. "You won't have to replicate the entire environment at home."

ISDN also means improved computer security. A feature called Closed User Group lets the customer specify a list of telephone numbers that are authorized to call a particular extension; if somebody from outside the user group tries to place a call, they get an error message. That should keep out the computer crackers.

This democratization of ISDN is very different than what telephone companies had planned for the technology in the mid-1980s. Back then, phone company executives "were looking for a killer application that would make everybody want to go out and buy ISDN," says Robert Toense, vice-chair of applications software interface of the North American ISDN Users Forum, and an electronics engineer at the National Institutes of Standards and Technology.

"People are beginning to come to the realization that no such killer application exists," says Toense. Instead, it is likely that people will use ISDN the same way they've been using modems – only more so.

Innovative Subscribers Desperately Needed
The basic thing that's been holding back the widespread adoption of ISDN in the United States has been "standards, standards, standards," says NYNEX's Gustafson. "We couldn't do it a few years ago because we hadn't deployed the technology. We hadn't agreed on a set of standards."

For example, regional telephone companies in the United States primarily use switches manufactured by AT&T and Northern Telecom. But until this year, the two companies' ISDN implementations didn't work with each other.

It wasn't until recently that the various players in the U.S. telecommunications market got together and decided upon standards for things as simple as the basic-rate ISDN connector. Until that was done, companies were hesitant to commit the millions of dollars necessary to install new equipment and software. It costs a few hundred thousand dollars to upgrade the software on a single central office switch; the interface cards in the central office for each subscriber's line cost $50 to $150 each.

Phone company executives had imagined their customers buying ISDN telephones to get features like hold and ANI, and then slowly, over the course of the decade, interconnecting the ISDN islands to form one national ISDN system. But customers ended up ignoring ISDN altogether.

"ISDN islands, where a company can talk to itself on its own business premise, isn't very useful," says Bellcore's Aloia. "Connectivity is the thing that the telephone company sells. A large degree of connectivity is the essential element, and it has been missing."

Things have been different overseas, primarily because the European countries and Japan still have their phones systems in the hands of single companies, usually state-run monopolies. These companies haven't had problems with software incompatibility because all of their telephone switches are made by the same vendor.

France is perhaps the furthest along on the road to ISDN. In the late 1970s, France made a commitment to bring its archaic telephone system into the digital age. Today, ISDN is available everywhere in the country. Installation costs $135, and the monthly fee is $60, according to Igor Douplitzky, assistant vice-president of new services at France Telecom's office in New York. More than 150,000 customers have basic-rate ISDN, Douplitzky said.

When more than one country has ISDN, it opens up the possibility of international high-speed data calls. "At least 50 U.S. companies use ISDN between France and the United States," Douplitzky says. Right now, that list is limited to companies that have made special arrangements to use the service.

But only for a few more months . . .

Inter-state Demo in November
Right now, the U.S. telecommunications industry is gearing up for Trip '92, the Transcontinental ISDN Project.

"We're going to begin with a 20-city network," says Aloia. "We've invited President Bush to actuate the "golden splice" – that's analogous to when the railroads got standard-gauge track from East coast to West coast."

With Trip '92, a person with ISDN service in any one of the 20 cities will be able to call a person with ISDN in any other of the cities and be guaranteed a digital path at 64Kbits/sec. The cities are likely to contain some of NeXT's largest customers.

"Unfortunately, they will have to be at relatively well-selected sites," says Toense. "The problem is that most of the switches in the telephone offices are not ISDN-capable right now."

Getting other cities on-line will decided on a case-by-case basis. Bellcore recently published Special Report SR-NWT-002102, which lists every telephone exchange in the United States and gives a date when those exchanges will be ready for ISDN. (The report costs $102 and can be ordered by calling 908/669-5802.) By the end of 1994, 54 percent of the telephone lines in the United States will be capable of handling ISDN.

As far as long-distance interconnection goes, MCI plans to be able to support ISDN connections in 80 percent of the cities in the United States by the end of the year.

But for many of us, the future will arrive in November.

Simson L. Garfinkel is a senior editor at NeXTWORLD.