Computer Telephony

You no longer need expensive, specialized equipment to add intelligence to your phone system. Using the new API standards TAPI and TSAPI, you can now link your computer or network to your phone system, opening up a wide range of applications.

Jon Udell

When the starting time of a high-school football game changes at the last minute, administrators must issue a flurry of phone calls to the sports community. In Denver, Colorado, a DOS-based PC running Dialogic telephony hardware and Telephone Response Technologies software largely automates the chore. It can even negotiate scheduling alternatives, according to Paul Kulas of Interactive Information Systems, whose partner ASO created the custom IVR (interactive voice response) system. "When an official gets a call from the IVR system about the change," says Kulas, "he can ag ree to the new time or, at the touch of a key, decline but volunteer for a different game--causing the system to make still more calls."

Computer telephony unites the two most essential business instruments--PCs and telephones--and it can't come a moment too soon. Work-flow automation isn't just about routing documents, it's about handling phone calls, too. Today you're probably working with the computer telephony equivalent of stone axes--voice mail, and maybe a PIM (personal information manager) outdialer if your company's PBX doesn't get in the way. Soon, thanks to efforts by Novell, AT&T, Intel, Microsoft, Apple, and a host of smaller vendors, you may enjoy much more powerful forms of CTI (computer/telephone integration). It's not a new idea. Corporate call centers have for years relied on intelligent telephony. Now call-control and voice-processing technologies are moving down to departmental LANs and individual office and home PCs.

No progress occurs in the computer industry without a sta ndards battle, so it's not surprising that computer telephony manifests itself to many observers as a war between TAPI, the Intel/Microsoft telephony API, and TSAPI, the AT&T/Novell telephony services API. In reality, the two are closer than partisans care to admit. Moreover, neither can directly support the kind of intelligent voice messaging used in the Denver sports program.

Both TAPI and TSAPI focus on call control. They enable computer control of dialing, answering, transferring, and conferencing. In PBX environments, they also support control of advanced features of digital telephones (TAPI) and the switches to which those stationsets connect (TSAPI).

Call-Control Applications

The most basic application of call control augments the 12 buttons on your phone with a PC keyboard and a GUI screen. Why? Most of the features of PBX systems lie dormant because no one can remember the button sequences used to activate them. "Every transfer in the world begins with the same four words: if I lose you," says Richard King, executive vice president and general manager of Novell's NetWare Systems Group. In the case of BYTE's AT&T Definity G3i PBX system, the description of its feature set fills two fat volumes.

In an increasingly cutthroat PBX business, switchmakers are highly motivated to ensure that the features they compete fiercely to provide are in fact accessible to users. On the other hand, users actually depend on relatively few of these features and aren't likely to invest in computer telephony just to simplify transfers and conference calls.

Call control becomes much more interesting when the computer can detect the called or calling number and react appropriately. In the classic application of Caller ID, an incoming call triggers a screen pop that launches the application or loads the document needed to handle the call. "You just can't appreciate how great this is until you see it work for you," says Gary Andresen, principal telecommunications analyst for Dataquest (San Jose, CA ).

Now that the FCC has ruled that long-distance and local carriers must exchange Caller ID information--the deadline to comply is April 1995--screen pops are ready to move beyond the 1-800 call-center environment into the realm of personal productivity. "The FCC decision will give small businesses the ability to use calling-number information that used to be available only to large companies in the form of ANI [automatic number identification] carried only on T1 lines," says Ellis Hill, a cofounder and director of Rochelle Communications (Austin, TX), a leading provider of Caller ID detection hardware, software, and development kits for DOS, Windows, OS/2, Macintosh, and Unix.

Will carriers meet the April 1995 deadline? It won't be as hard as you might think. "When I called a fellow in Canada the other day," says Hill, "he picked up and said, 'Hi, Ellis.' I called Sprint's product manager to congratulate him for passing the CPN [calling party number], and he said, 'We're doing what?' Two weeks later, they shut it down." Major carriers already operate the hardware and software needed to transmit Caller ID information, and, as Hill discovered, that feature can sometimes be enabled by accident.

Other applications that cry out for call control are whiteboard products such as Fujitsu Networks Industry's DeskTop Conferencing and IBM's Person to Person. These applications, which enable a group of users to annotate shared documents across LANs and WANs (wide-area networks), assume that those users will also be connected through the phone network in a parallel voice conference. When these applications are enhanced with call control, users will be able to set up the voice and data layers of the conference in a single step.

The most advanced call-control applications are power tools for sales and collection agents working in high-volume call centers. When you call an 800 number to place a credit-card order, an ACD (automatic call distributor) routes your call (and perhaps your purchase history) to the sales agent with the shortest queue. If you are delinquent in paying a bill, a predictive dialer cycling through a list of deadbeats may call you. Only after you pick up and establish to its satisfaction that you're not an answering machine will it connect you to a collection agent and send information about you to the agent's screen. As these tools find their way into the hands of smaller, more mainstream businesses, you can expect better service in some cases and more efficient harassment in others.

Ultimately, the richest applications of computer telephony blend call control with media control--that is, the ability to send and receive voice, fax, digital data, and perhaps video through a telephone connection once it's established. There's a lively debate about how the new call-control APIs, which don't directly support media control, will intersect with the rapidly evolving voice-processing industry. To understand the terms of that debate, though, it's helpful to review the architectures of TSAPI and TAPI.

NetWare Telephony Services

In the late 1980s, products from DEC (CIT) and Rolm/IBM (CallPath) pioneered the use of a CTI link between a PBX and a host computer. Charles Jolissaint, now chief technical officer of Edify (Santa Clara, CA), holds a patent on the CallPath technology he developed while employed by Rolm. "The switch knew about the call," says Jolissaint, "and the host knew about the caller, so by marrying the two you could keep the call context displayed through a series of interactions with VRUs [voice-response units] and various agents."

NetWare Telephony Services, which shipped May 16, recapitulates this theme, substituting a NetWare server for the traditional mainframe and NetWare clients for the traditional terminals. Initially, telephony applications will run on two platforms: NetWare servers and Windows PCs. Additional clients will include UnixWare (now in testing), Macintosh, OS/2, and DOS. "You want to have the same API available to server and client applica tions," says Gerry Plummer, applications development manager for software ACD vendor Teloquent Communications (Billerica, MA), "and that's a nice feature of the Novell architecture."

AT&T's Definity was the first PBX supported in this way, but Comdial, Fujitsu, NEC, and other switchmakers (the notable exception at press time being Northern Telecom) signed onto the plan as well. AT&T claims that together these partners account for 70 percent of the U.S. PBX-connected business phones and 50 percent of the international ones. To support NetWare Telephony Services, a PBX vendor provides a physical link between switch and server and supplies one or two drivers (NLMs, or NetWare loadable modules) to control the link and map client requests to the PBX protocol. The requests that clients send to the telephony server NLM and that it passes along to the PBX driver conform to the CSTA (Computer-Supported Telecommunications Applications) standard defined by the ECMA (European Computer Manufacturers Association).

The CTI Link

The nature of the critical switch-to-server link varies from switchmaker to switchmaker. Comdial requires no hardware (its DXP switch uses an RS-232 serial interface) and gives away the drivers, but it charges for the "key" that turns on the telephony services/CTI commands in the switch. AT&T, on the other hand, charges $1500 for the communications board for its Definity system. That's a fraction of what you'd have paid just a year ago. Throughout the PBX industry, formerly prohibitive CTI link prices are in freefall, signaling the eagerness of switchmakers to attract PC-based telephony applications.

Novell says you'll pay $75 to $200 per seat for NetWare Telephony Services, depending on the number of users (and not including the cost of the link). If you're not running current PBX hardware and software, though, you'll need to upgrade, and that can be painful. "I have an AT&T System 75; it does a great job, but there's no migration path," says Dave Straitiff, executive vice presid ent of Voice Technologies Group (VTG; Buffalo, NY). "Stepping up to the Definity can be a $30,000 forklift upgrade."

Even so, Novell argues, deployment of NetWare Telephony Services is a centralized, manageable exercise, and the costs can amortize over a large population of PCs. There's no telephony hardware on the desktop, as is typical of TAPI, so you avoid the cost and considerable hassle of installing that hardware. "During our beta test, we just E-mailed users the client software and instructions they needed to get up and running," says Novell product-line manager for NetWare Services Scott Wells.

With TSAPI, the connection from phone to PC is logical, not physical. When you log in, you create a mapping between your Ethernet and phone addresses. That association synchronizes CSTA traffic flowing on the LAN with telephony traffic flowing on the PBX. When you log in from elsewhere than your desktop PC, you can supply the extension of the closest phone and so preserve telephony services.

What about remote users dialed in to the LAN? Off-premise PBX extensions exist, but they're expensive and not mobile. Art Schoeller, AT&T's market director for client/server telephony, recommends instead that the remote user dial in to the PBX using a feature that enables the phone to appear as a station on the switch. "It's analog, so you don't get all the goodies," says Schoeller. But standard features are available, and he points out that when you need to set up a conference call from a hotel, you'll save money by using the services of your own PBX rather than those of the network. Note that with TAPI, you'd need a digital telephony driver for the office and an analog or ISDN one for the road. A TSAPI client doesn't need a telephony driver at all, because it shares the one that's in a NetWare server.

The Novell/AT&T approach supports third-party call control. That means a third party--a human or software agent--can establish connections on behalf of two or more other humans or software agents. TAP I, by contrast, emphasizes first-party call control, which means that the initiator of a call is also necessarily a party to the call. Third-party call control flourishes in production call centers, where software agents often initiate and control calls.

How important is this technique for ordinary office environments? That's the subject of another lively debate (see the text box "First-Party vs. Third-Party Call Control"). What is clear is that, given direct access to the state machine that the switch uses to represent call progress, connections, and other events, programmers can endow third-party call-control applications with sweeping supervisory power. With that power comes responsibility. A malicious TSAPI client could be a formidable wiretapper. Novell therefore extends NetWare security into the telephony services realm, defining new call-control privileges and supplying an administrative tool to manipulate them.

This central administration is an advantage. However, while it clearly invit es various kinds of directory synchronization, none is automatic. TSAPI clients running on NetWare 4.x, for example, will likely want to use the NDS (NetWare Directory Service) as a company dialing directory. The clients can be programmed to do so, but the TSAPI client library doesn't natively support NDS or any other directory service. Nor does it provide a standard address-book mechanism like those supplied by VIM (Vendor-Independent Messaging) and MAPI in the E-mail world. Neither does TAPI, by the way. Both telephony APIs can, of course, call VIM, MAPI, or other address-book services, but these mechanisms aren't standard, as they are with the E-mail APIs.

Another interesting possibility is joint administration of the PBX and NetWare directories--potentially a major time-saver. Applications can be written to synchronize the two, but that's not a standard feature of the system today. It probably couldn't be, given the diplomatic gulf that can separate administrators of voice and data networks. "Depen ding on who's carrying the keys to the closet, you tie the phone to the LAN or vice versa," says Jeff Hafer, telecommunications manager for electric utility company GPU Service (Reading, PA). "In some cases, it'll be like Iran and Iraq."

Windows Telephony

Jointly developed by Intel and Microsoft, TAPI uses the now-familiar WOSA (Windows Open Services Architecture) formula. A system extension, TAPI.DLL, presents a common telephony API to applications developers. The TAPI layer, in turn, talks to one or more service providers that translate common requests into the protocols used by various flavors of telephony hardware. The sample service provider that comes with the TAPI SDK (Software Development Kit; released in late November 1993) controls Hayes-compatible modems using AT commands.

A variant (which Microsoft made available on CompuServe) works with so-called AT+V modems like Zyxel's U-1496E. Like the more powerful and sophisticated Dialogic and Natural MicroSystems boards, these modems can receive and transmit voice and the DTMF (more commonly, Touch-Tone) signals used in analog telephony. The +V refers to the ISO extensions to the Hayes AT command set used to control the modems' telephony features.

PBX vendors and third parties are also working to develop TAPI service providers for devices that emulate the digital phones that connect to PBXes; in these cases, transparently to the TAPI application, call-control messages are out-of-band digital signals instead of in-band DTMF tones. Other products for which TAPI service providers exist or are being written are DSP-based (digital signal processor) multifunction boards such as Sierra Semiconductor's WaveFax, National Semiconductor's TyIN 2000, and IBM's MWave.

Novell argues that TAPI is limited by a requirement for local telephony hardware and a restriction to first-party call control. In principle, that argument is wrong. Nothing prevents a TAPI service provider from sending requests across a network to a call-control server that t alks to telephony hardware, perhaps even on a third-party basis. "We proved that at the Computer Telephony show," says Microsoft's product manager for TAPI, Charles Fitzgerald. "We showed TAPI applications front-ending Q.Sys International's CallProducer [a LAN-based telephony server]." In practice, however, Novell's claim is largely true. TAPI, like the Macintosh Telephone Manager, focuses more on the desktop or small office than on the enterprise (see the text box "Macintosh Telephony" on page 89).

Will TAPI integrate with TSAPI? Virtually everyone interviewed for this story expects that it eventually will. Clearly, if TAPI can be made to talk to a Q.Sys server, it can be made to talk to NetWare telephony servers as well. Until then, TAPI and TSAPI will tend to gravitate toward opposite poles. "We see TAPI serving the home user or small business, or maybe providing personal voice mail within a larger corporation," says Rod Kuhn, lead software engineer at Active Voice (Seattle, WA), a vendor of voice- processing servers and applications. "At about 25 users, though, people will start to look at justifying costs by using [Novell's] telephony services."

Note, though, that TSAPI won't be an option in all PBX environments, nor is it yet supported on any Centrex system. Switchmakers typically offer a family of products, including low-end key systems, various PBXes, and possibly Centrex systems as well. Because only the top-of-the-line PBXes will initially support NetWare Telephony Services, PBX vendors are looking to TAPI as a way to bring the other members of the product family into the fold. "With a service provider that makes the PC look like one of our digital stationsets," says Michael Gough, director of marketing for Comdial Enterprise Systems (Charlottesville, VA), "we'll have a solution from our basic 408 (four lines, eight stations) key system all the way up to our 224-port DXP switch."

The technology Comdial needs to deliver TAPI support is coming from VTG, developer of the Scorpion platf orm, a family of board-level products that will emulate a variety of digital stationsets and natively support others, the first being Comdial's. "We've taken that work and put it into a TAPI context," says VTG's David Straitiff. "The base design gives you TAPI integrated with Microsoft sound and 14.4-Kbps fax/modem capability on a single ISA board."

Lines and Phones

Two abstractions are central to TAPI: the line and the phone. Line devices (e.g., AT+V modems, PBX interface modules, and ISDN cards) supply one or more communications channels. Much of TAPI is concerned with call control, so most of the functions operate on line devices. But unlike TSAPI, TAPI applications can also wield considerable control over feature-rich phone devices. Functions that operate on phone devices can control the volume and muting of speakers or the gain of microphones (in handsets, headsets, and speakerphones), read and write the display of a phone equipped with one, and even reprogram a phone by downloading instructio ns or data into its memory. "It's very complete. I was surprised to see how thoroughly they're supporting all the things you find on the various feature phones," says Edify's Jolissaint.

One consequence of the TAPI approach is that the phone can serve as a WAV audio I/O device and can be used for a variety of purposes. "For example, I can ring your phone independently of the PBX to announce an incoming message," says David Straitiff. Phones are ubiquitous and private. If you're sitting in an open cubicle, you'll probably want to play back your voice mail through your phone handset or headset, not a pair of Labtec speakers hooked to a SoundBlaster. Alternatively, you might dispense with the phone entirely and attach a headset directly to the TAPI board, although that means that your phone won't work if Windows isn't running.

How can TAPI call-control functions play voice-mail messages? They can't, but the Windows wave audio functions can. TAPI does offer a function, lineGetID, that you can use t o extract a handle to the wave device associated with a line device--for example, the sound component of a Zyxel modem or a VTG Scorpion board. The API of choice for data or fax media streams is, at the moment, the admittedly inadequate Hayes AT command set. Microsoft says that the improved communications driver forthcoming in Chicago (Windows 4) will offer a superior API for data and fax modems. Radish Communications Systems' VoiceView technology, which enables alternate voice and data exchanges on a single line, is widely expected to become another important transport that TAPI applications will use to exchange data.

Another TAPI function, lineMonitorMedia, enables an application to distinguish among incoming voice, data, fax, and other types of calls. (Service providers will also classify incoming calls.) This ability to classify calls supports a model in which multiple telephony-aware applications may be active concurrently. A well-behaved TAPI answering machine might, for example, register interes t in voice calls. When it detects an incoming fax, it passes the call along to a registered fax application; the fax program, in turn, passes voice calls to an application that wants them--in this case, the answering machine.

Although Novell plans to add an arbitration mechanism for workstations in the future, TSAPI presently lacks an analogous concept of multiple cooperating applications. Is that a problem? Not according to Paul Gasparro, CEO of Aurora Systems (Acton, MA). Aurora's FastCall is middleware that sits below applications but above various telephony APIs, including TAPI, TSAPI, AT&T's PassageWay, and Northern Telecom's Visit. "We link the API to the application," says Gasparro, "and we route calls according to rules you specify--if it's my stockbroker, do one thing; if it's my wife, do another." TAPI's model for cooperating applications is somewhat anarchic. Gasparro argues that users will inevitably elect one application or middleware component to impose systemwide order.

What is In tel's relationship to TAPI? The codeveloper of the standard has dropped off the radar screen for the time being. Widely rumored to have been developing a line of PC telephony hardware whose potential TAPI would unlock, Intel is now running deep and silent. "Look at the products we already have [ISDN videoconferencing, fax modems]," says Intel public-relations manager John Jackson. "Clearly these will benefit from TAPI."

Real-World Computer Telephony

While people in the computer telephony business invariably applaud the arrival of TAPI and TSAPI and pledge to support them, the fact is that neither has yet to make much impact on an industry that was already thriving rather nicely without them. Telephony hardware from Dialogic, Natural MicroSystems, Rhetorex, and others has been finding its way into a variety of PC-based applications.

The InfoLine audiotex system recently installed by my local small-town newspaper, the Keene Sentinel (Keene, NH), is one example. I can call for weather or sports information and, more interestingly, the public library's children's story of the week or the humane society's narration describing the animals available for adoption. A 486-based DOS PC with a 525-MB drive and a pair of four-line Dialogic cards manages 42 hours of voice files. There's also a priority line so the school superintendent can record announcements on snowy mornings. A linked PC provides Associated Press stock quotes.

Speech-recognition capability means that rotary callers can make selections by speaking at a prompt. This humble use of speech recognition (along with slightly more sophisticated ones that, for example, allow data entry) is currently one of the most practical, of benefit to the 10 percent to 20 percent of U.S. phones with rotary dialing and to the much higher percentages of rotary phones in many other countries. "We can also forward calls, collect messages, and conduct surveys on behalf of information providers," says InfoLine audiotex manager and account executive Jon Foster.

What's in it for the Sentinel? It sells the ads that callers must listen to before hearing most selections. Evidently, that's not a major deterrent. In a local exchange area with a population of 70,000, the system handles 1000 calls a day.

IVR--essentially database lookup using Touch-Tone input--is increasingly a method of choice for companies that need to transmit information to their employees or to customers and vendors. Need the CMOS drive table settings for a disk drive? If you're lucky, the vendor runs an IVR system that can speak the information to you seven days a week, 24 hours a day. A variation on this theme is fax on demand. In this case, your Touch-Tone input yields a fax, perhaps one that illustrates jumper settings on a board. Nowadays, customer service is almost entirely delivered through the telephone, and the quality of that service is a key competitive factor. Companies that thoughtfully and effectively deploy computer telephony will have happier customers.

We're only beginning to tap the potential of computer telephony to streamline business operations. At General Electric, another application built by Interactive Information Systems (using Telephone Response Technologies' tools) automates work flow in GE's property management division. GE, which owns thousands of properties around the country, had been requiring realtors and contractors to file reports and completed work orders by mailing or faxing them back to the central office for data entry. "We changed it completely," says Paul Kulas. Now the field workers do much of that data entry themselves via Touch-Tone input. "And they love it," says Kulas, "because they get instant confirmation that they've started the process that cuts their paycheck."

Edify's Electronic Workforce is another toolkit that puts voice and fax response at the service of work-flow automation. Server-based agents, coded using a visual programming language, can process Touch-Tone E-mail and fax input, look up information in databases, send f axes and E-mail, and pump information into DOS-, Windows-, and OS/2-based applications. In a typical application, a customer calls in and places an order via Touch-Tone input. The agent running on the OS/2 server might check the availability of the ordered item via an Oracle query, fax a confirmation to the customer, send a Notes mail message to the product manager, and insert a record describing the caller into a telemarketer's Act! lead-tracking database.

Still another platform for developing telephony applications is Lotus Phone Notes. A joint effort of Lotus Development and Simpact Associates (San Diego, CA), Phone Notes evolved from Simpact's Remark LANClient and PhoneClient, which integrate voice into Notes documents. LANClient uses the phone as a convenient I/O device and the isochronous PBX system as an effective transport. When you begin recording an annotation, LANClient signals the Remark Voice and Telephony server, which instructs the PBX to ring your phone. The voice server then records wh at you say in files that it controls or, for portability, in Notes databases.

With Phone Notes, further integration between Notes and the Remark server enables the development of true voice processing applications. Phone Notes, the toolkit Notes developers use to create those applications, is a Notes database with 17 forms that work like an IVR scripting language. You use some forms to create and manipulate Notes documents, and others to perform telephony functions like dialing or text-to-speech output. PhoneClient, which was the first engine capable of executing Phone Notes applications, enables the telephone to function as a limited Notes client. Callers can access Notes databases, enter voice and numeric data, and retrieve voice, numeric, and (with the optional text-to-speech module) textual information.

How's the quality of the text-to-speech output? "It's improving, " says Simpact's vice president of marketing, Steve Adams. "You can have the fields read out of a sales-order database, but y ou probably don't want to listen to the text of a Dow Jones report." Developers are building systems to support help desk, event registration, human resources benefit selection, and sales support applications, according to Phone Notes product manager Loretta Jones.

In some cases, computer telephony applications are so strategic that people won't even discuss them. "We're continually surprised by the visionary ideas integrators come up with," says Bob Edgar, president of Parity Software Development (San Francisco, CA) and author of PC-Based Voice Processing (Flatiron Publishing, 1994). Edgar describes Parity's VOS Development System as "the Clipper of voice," a common language for developers of turnkey voice-based systems. Edgar won't say what kinds of applications Parity's best customers are building: "They trust me not to give away their competitive advantage."

Unified Messaging

An application of computer telephony that will grab virtually everyone's attention is unified voice, fax, and E-ma il messaging. Everyone would like to be able to randomly access these different message types from a single inbox. Some solutions are here today. Applied Voice Technology's CallXPress3 Desktop presents voice and fax messages in a single inbox, with future support planned for E-mail. The same holds true for Active Voice's TeLANophy (ViewMail and the forthcoming E-Mail Notify/Delivery). Centigram Communications also plans to integrate E-mail into future releases of its OneView. For now, OneView handles voice and fax in a single inbox and lets you combine the two in compound messages, according to Ben Tang, manager of product marketing. Centigram's TextMemo lets you listen to your E-mail over the phone. VMX (now the Octel Client Server Software Division) unifies voice and E-mail today; its VMXmail puts voice mail directly into Microsoft Mail and cc:Mail (and soon Lotus Notes) inboxes.

While these first implementations of unified messaging are intriguing, most observers agree that truly robust solutions ar e yet to come. For voice- and call-processing vendors such as Active Voice and Applied Voice Technology, delivering GUI control of the voice mailbox was an obvious way to enhance their products. Expensive, fixed-function voice-mail systems like AT&T's Audix are now being challenged by more flexible, PC-based third-party systems, not only for reasons of cost, but because the new systems can do some very interesting and powerful things.

When you play a voice message, for example, you're likely to want to reply. Active Voice's TeLANophy initiates the return call with a mouse-click. A caller who transmits a fax may be prompted by the voice server, Repartee, to attach voice annotations to the fax. Repartee also supports dynamic, real-time message handling. "Suppose you call me at 1 p.m.," says Active Voice's Rod Kuhn, "and I'm expecting an important call from my boss around the same time. With ViewCall (due in the third quarter), I can be alerted that my boss is holding for me at the auto-attendant while I' m talking to you. If multiple calls are stacked up there, I can view them and choose which to connect to." Voice servers wielding a combination of call-control, IVR, and voice-mail technologies are increasingly able to add intelligence to the basic switching provided by the PBX. That's a fascinating development, with far-reaching implications, but it doesn't in itself lead to the unification of voice mail and E-mail.

Dennis King, executive vice president of market development at Applied Voice Technology, believes the future of unified messaging lies with messaging engines such as those forthcoming from Lotus (Lotus Communications Server) and Microsoft (Enterprise Messaging Server), built to handle large binary objects as well as text. To integrate voice and E-mail today, you have to cross-reference separate message stores. These links, which can be fragile enough to maintain in a single location, can become unsupportable in a distributed environment. "If I have my E-mail and voice-mail systems tied tog ether in Chicago," asks King, "and Chicago connects to New York on the corporate WAN, how do I replicate the voice functionality over in New York?" It can be done, counters Bob Greco, vice president of product development for Active Voice, and it has to be, because even when voice and message stores consolidate locally, there remains the hard problem of distribution.

Anywhere, Anytime

Phones achieve a kind of invisibility. They melt into the woodwork. You use phones unconsciously (unlike PCs), and while that's a great thing for most people, it's a problem for those pushing computer telephony. Harry Newton, publisher of Computer Telephony and Teleconnect magazines and promoter of the annual Computer Telephony show in Dallas, likes to point out that with 99 percent of the world's phones, you can't even backspace to correct a miskeyed entry. What's even more amazing is that the average computer user never thinks to complain about the lack of a feature that, if missing from a software application, would raise instant howls of protest.

Computers can help phones become much smarter than they are now, in ways that both subtly and dramatically change how we live and work. The rate-limiting factor isn't technology, but imagination. Because people don't see phones for what they really are--ubiquitous, user-friendly terminals that connect anywhere, anytime--it's hard to envision computer telephony applications, and harder still to cost-justify them.

"It's great to have Harry Newton out there evangelizing," says Paul Kulas, "but he's the only one who's making money. It's tough to sell a bean counter on intangibles. They say 'that's really neat.' They don't ask 'how much is it?' " That's a healthy skepticism. It can change quickly into technology lust, though, as more early adopters demonstrate real competitive advantages.

Home financial services

Citibank has joined forces with Philips Home Services to deliver financial services via a screen phone. Home customers can use the pull-out keyboard and menus shown on the Philips phone's LCD to perform bank transactions.

Healthcare

Aetna Life & Casualty (Hartford, CT) sets up voice-response lines for small businesses, whose employees can call to get claim or spending-account status. The company also manages pension funds for other businesses. Employees in those businesses can call a voice-response line to check the status of the fund or select other investment options. Aetna's own employees use voice response to enter time-card information and for benefits enrollment.

Customer support

Compaq Computer customers can get faster, better on-line support by typing in their customer IDs using their phone's keypad. The IDs are routed to a customer database on the network, which tells the PBX which customer-support agent it should route the call to. That agent can then immediately call up on his or her computer screen all the appropriate background on the customer.

Mail order

Gateway 2000 is looking into the possibility of using CTI (computer/ telephone integration) to automate order-status queries. Richard Birkenbeuel, MIS director for Gateway, is examining a voice-response system that asks the caller for his or her order number, ZIP code or other confirming information, and any other required information. No human would need to be involved at Gateway's end to check order status. Where interaction with a person is required, the system would first get the necessary information from the customer and route it with the connection to the agent. That information would then "populate" the agent's screen so that he or she could immediately deal with the customer.

Report filing

General Electric's property management division has automated report filing for its realtors and contractors. These agents now call in and enter their reports using Touch-Tone input.

Customer service

Federal Express (Memphis, TN) has installed voice-response systems in its call centers. Customers can call an 800 number over an ISDN connection. Using ANI (automatic number identification), the system routes the call to an agent and automatically displays the appropriate information on the agent's computer. The customer can also choose automated voice response to get the status of a package, shipping rates, or pickup schedules.

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Illustration: TAPI (or GeoPort on the Mac) allows a single user or small business to integrate the phone and computer systems. This can be done using digital PBX or ISDN or analog POTS (plain old telephone system). The benefits of personal computer telephony include user-controlled installation and personalized service.

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Illustration: In a network environment, there is no direct phone/PC link. Instead, the two systems are linked via a telephony or voice server. Telephony servers with digital connections to a switch can offer more sophisticated call control than those with analog connections.

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Photograph: Phones are becoming optimized for interaction with computer systems. The Philips P 100 screen phone, for example, provides an LCD and a pull-out keyboard.

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Jon Udell is a BYTE senior technical editor at large. You can contact him on the Internet or BIX at judell@bix.com .