(FORTUNE Magazine) – YOU ARRIVE at the hotel, pop your smart card in a doorway slot to introduce yourself, then go straight to your room, assigned earlier by computer. To enter, say your name, and the door magically opens. You hang up your coat, punch in channel 162 on the TV, and hold a videoconference with colleagues. When the meeting ends, you flip to another channel to shop for a gift, then call home on the videophone to see how the family is faring while you are on the road. As Daniel Burrus, author of the new book Technotrends, says, ''The future is already here.'' Scenes like the one above will be commonplace soon, because companies like the hotel chain Marriott are listening to their customers and scurrying to satisfy their demands with just the right combination of high and low tech. Hotel guests frequently complain about time spent at check-in. So Marriott launched a new program called 1st 10 that virtually eliminates the front desk. Pertinent information such as time of arrival and credit card number is collected when the reservation is made, thus reducing check-in time from an average three minutes (higher at big convention hotels) to 1 1/2 minutes. Marriott someday hopes to lower it to seconds, with the help of smart card technology.

To make better use of the room, the chain will also roll out videophones so that guests can visually communicate with clients, colleagues, and family. In- room videoconferencing may arrive at Marriott before the new century does. Says Stephen P. Weisz, a senior vice president of sales and marketing, echoing the words of many service industry executives: ''We don't want to just satisfy our customers -- we want to delight them.'' Companies determined to delight customers in the 21st century are preparing for the day when technology will personalize customer service in utterly new ways. Don't always expect consumers to catch on immediately, though. Says Thomas I. Rubel, a partner at Price Waterhouse's Management Horizons division: ''You've got the technology in one hand, and Bubba and his wife, who may not accept it, in the other.'' Better be ready for both, because invariably customers will expect delivery on their own terms. Customer service experts say that trends for the 21st century are already taking shape. Some, such as self-service, you know about -- or at least you think you do. Others, such as mass customization and relationship marketing, are gathering momentum and ready to explode.

The latest consultant jargon for self-service is disintermediation. Whatever the name, ''What we often call customer service is really customer self- service,'' says Paul Saffo, a research fellow at the Institute for the Future in Menlo Park, California. Consumers got hooked on high-tech self- service when automated teller machines revolutionized their lives in the late 1970s. Machines, they learned, are often faster and more reliable than humans. Companies happily empower customers to serve themselves because it usually means big savings, a perfect fit with the universal corporate budget squeeze. Replacing high touch with high tech is not always as straightforward as it seems. After all, even high-tech junkies are comforted knowing that a person is nearby when a machine falters. Says Saffo: ''The real frontier still to be crossed in self-service technology is human intervention. When do you put humans in the loop, and when is it appropriate to keep them out?'' And who pays for them?

In general, customers will pay more for humans to serve them. But some companies are charging just as much for high-tech services that cost less than human ones. More than 10% of all U.S. banks charge customers for using an ATM. The banks reason that customers value the service enough to pay for it. In the 21st century companies will always charge customers for the convenience brought by high tech, Saffo says, ''but they will be sneaky about it.'' Rapid advances in hardware and software will continue to drive disintermediation, making self-service easier and more fun -- two essential requirements for mass consumer acceptance of any new technology. With voice-recognition technology, for example, customers simply speak to a computer, as at that hotel of the future, instead of pushing buttons or typing. Although a staple of sci-fi films and TV shows since the 1950s, this technology has frustrated scientists for decades. AT&T, which has been coaxing machines to recognize human speech for 40 years, says the hard-won technology is finally out of the lab. ''Voice recognition will be ubiquitous by the year 2000,'' asserts Greg E. Blonder, a research director at AT&T's Bell Laboratories. Even disinterested observers agree that voice recognition will soon bow at your favorite bank, restaurant, hotel, library, and mail-order house. You'll know it has really arrived when you go to the ATM and receive 50 bucks for the asking. By combining voice recognition with artificial intelligence, AT&T's Universal credit card outfit is planning what it calls a 21st-century personal servant for its 17 million-plus cardholders. ''In our research, customers tell us they would love to have a Jeeves in their lives,'' explains Hans Hawrysz, executive vice president of marketing and business development. ''The average household gets between 20 and 30 different statements per month, and people would love to have someone take care of those bills for them.''

UNIVERSAL'S personal servant (PS) proposes to do the job. The cardholder will communicate with PS via phone or computer (pen-based will be fine). The PS will make hotel reservations, balance the checkbook, and do any number of mundane chores. It will even make recommendations, such as ''Jack, the Ralph Lauren outlet is having a sale on men's shirts. Should I order you a few?'' Most remarkably, says Hawrysz, the cardholder will be able to design the voice and personality of his or her personal servant. If the Arthur Treacher or John Gielgud butler type doesn't please you, create one that is more like Marilyn Monroe or Madonna. To deliver service anywhere, anytime, companies are turning to instant- access machines such as the personal communicator -- a hand-held, mobile device that is a combination pen-based computer, cellular phone, fax machine, pager, electronic agenda, and E-mail box. This everything machine bridges distances of space and time and enables users to stay in touch with customers in distant locations at any hour of the day or night. ''The personal communicator will revolutionize customer service,'' says Technotrends author Burrus. Apple's much heralded Newton grabbed all the headlines, but technology watchers say AT&T's two wireless versions, introduced last spring, may have the right stuff. Privately held F.D. Titus & Son, a distributor of medical supplies, is equipping its entire 144-member sales staff with AT&T's EO 880 personal communicator. With the tap of their fingertips, sales reps have ready access to information about the 14,000 products in the company catalogue, and they can send a fax to a customer when stalled in freeway traffic. Says sales representative Don Durben: ''Having everything you need to service customers in one place is a whole new way of working. Before, I had to carry around a book with the customer's history, our thick catalogue, and my agenda. Now I have everything in one place, and I can answer a customer's questions on the spot.'' By 2000, personal communicators, now priced between $1,600 and $3,000, will follow the way of all technology and be smaller, faster, cheaper, and easier to use. Among the many advances will be two-way videocommunication and the ability to send and receive high-resolution graphics, in addition to faxes and E-mail. The one person/one product approach -- mass customization -- is a customer service trend that is gaining speed everywhere. Jennifer Brotman, a senior vice president at the Boston consulting firm Forum Corp., says, ''The trend is that customers want it the way they want it, and the companies that figure out how to do that will take the lead in the next century.'' Mass customization will include far more products than the ones you'd expect to be tailored for use, such as cars, bicycles, computers, and financial services. Says John Myser, a group vice president at 3M's commercial and consumer markets group: ''We've been shipping out truckloads of 100-sheet Post-it note pads to Wal-Mart for years, even though their customers may only need 42 or 67 sheets. Now,'' Myser acknowledges, ''Citizen Customer says, I don't want it the way you give it to me. I want to be free to choose.'' The Minnesota giant is still working out the hard part, how to make a profit, but it plans to deliver a host of customized products to global customers. If Britain's giant W.H. Smith stationery chain wants 50-sheet Post- it pads in alternating neon colors, 3M will deliver. Meridian Bancorp, headquartered in Reading, Pennsylvania, intends to offer customers high-tech, low-tech, and mid-tech service and provide it on the phone, on TV, at the ATM, and at branch offices. Says Joseph F. Pendleton 3rd, a senior vice president at Meridian: ''I'll let our customers tell me how and where they want to bank.'' The bank's Paradise, Pennsylvania, branch, in the heart of Amish country, has hitching posts for horse-drawn buggies. By contrast, Meridian's full- service ''bank of the future'' features an array of high-tech services, including two-way video remote terminals for customers who want to see and talk to a live representative while on the street. A simplified version of the terminal, which Meridian calls BankSpot, is being tested now. Blockbuster Entertainment, the nation's leading movie retailer, plans to stay on top by combining smart technology with smarter workers. George Johnson, who owned the most franchises, was brought in last summer to upgrade the humans. Johnson is encouraging employees to view five movies a week at home so they can better handle customer queries about film content. He also has the Gallup Organization interviewing customers daily to find out, among other things, the characteristics of an ideal salesperson. Beginning next year, Johnson plans to tie employee compensation to customer satisfaction. On the high-tech side, Blockbuster is exploring myriad new services and technologies, including interactive TV shopping and electronic distribution- on-demand for its video and record outlets. Instead of browsing through bins, customers can enter a cash machine-like kiosk, punch in the title of their desired compact disk, video, or computer game, and summon it from digital storage files within minutes. The selection will then be recorded onto a blank disk or tape for the customer to take home. With electronic ordering, the customer's requested disk or video will never be out of stock, a fate befalling 43% of music shoppers today. Explains the South Carolina-born Johnson: ''We have to constantly increase the level of customer service, because what is accepted today will not be in 18 months.'' Relationship marketing -- getting companies and their customers ever closer together -- is another trend gathering steam. If you accept that winning companies of the 21st century will customize products and cater to individual styles, then they'll have to learn a lot more about their customers to do it effectively. ''Companies will have to get close enough to their customers to form friendships,'' says John Parkington, a consultant at Wyatt Co. ''They have to make heroes and heroines out of the people who use their products.'' To do that, companies will have to gather as much information about them as a personal dating service. Jennifer Brotman of Forum Corp. says that the typical, cold Q&A consumer surveys that most companies use do not provide enough rich information to yield a close understanding of customers. She says, ''It is important to get the voice of customers, to capture their words, in order to really understand what they want.'' You can get that close, says Michael S. Malone, co-author of The Virtual Corporation, only if supplier and customer reach a level of mutual trust by forming what he calls a ''co-destiny relationship.'' That's just what Gary Borgstadt, a manufacturing engineer at 3M's medical and surgical products plant in Brookings, South Dakota, had in mind when he designed a low-tech program called Pulse. All 750 employees, from production- line workers to senior executives, meet face to face with customers, mostly doctors and nurses, at three area hospitals. Employees don scrubs and go into the operating rooms to watch their surgical tapes, drapes, and prep solutions in action. Says Borgstadt, apparently no pun intended: ''We get to feel the pulse of our customers. We see their problems and frustrations up close.'' The work teams observed that some products' packaging was difficult to open, and others', designed for reuse, could not be easily closed. They suggested to 3M's product development people that a Ziplock-type opening and closure would make their customers' jobs easier. The suggestion became reality within a few months. Says Valerie Smidt, staff education coordinator for the operating room at Sioux Valley Hospital in Sioux Falls, South Dakota: ''The 3M people give us pointers on how to better utilize some items, and we in turn suggest how to make some of their products more user-friendly.'' The hospital staffs have also been giving the company an unsolicited wish list of future products, which 3M has been evaluating. Most important, Borgstadt says, is that face-to-face interaction has made every worker at the Brookings plant, and at other Pulsed factories, more conscientious about delivering a great product. Suppliers often have the ammunition already at hand to make them better relationship marketers. They just don't know it. David Huntoon, a vice president of the research firm Thompson Associates, says retailers are notorious for having databases that do not speak to one another. ''The marketing department will have a consumer database, real estate will have another, and distribution will have one.'' If only the information from those disparate databases were assimilated, the retailer would have an awesome profile of its customers.

COMPANIES often turn to parallel processing computers to pull varied sources together and attack a problem. Banks, for example, have been using NCR's massively parallel computing system to help coordinate credit card solicitation. Tapping various sources, including upscale catalogue companies, credit verifying services, and the bank's many databases, massively parallel computers work up a profile of prospective candidates, including an A list of names for special attention. Note that NCR first used massively parallel computing for retail inventory control. That's another thing about technology -- it doesn't always do what you think it will. ''My rule is to never use technology as it was originally intended, because your competitors will be doing that,'' says Burrus. With bumper-to-bumper traffic expected on the vaunted information superhighway, consumers are apt to be blinded by the glare of oncoming technologies. Whether offering hotel rooms, banking services, or plumbing supplies, customer service exemplars of the 21st century will dim the high beams where necessary and smooth the rough spots out of the road. Remember, some customers will want to be chauffeured, others will want the wheel themselves. Some will speed, and others will take it slow. One way or another, all will be in the driver's seat. It's just a question of which companies they pay for the ride.