Voice Communication in Business Volume 2
Essays on telecommunications, 1981-2002

There have always been people who want to see the person they're talking to, and inventors who want to win their business. I even have a book, Tom Swift and his Photo Telephone, copyright 1914, in my library to prove it. But making any form of picture telephone happen is harder than it looks. I wrote this for the September, 1990, Business Communications Review.

Can Your PBX Switch TV?
(Business Communications Review, 1990)

"ICA was all video," Fred said. "Two-way picture connections! Can PBXs handle it?"

Fortunately for me, we were making a conventional audio telephone call. Thus I couldn't see Fred, tie loosened, hair awry, steam coming out of his ears as he contemplated the latest advances in technology, presented to him in glowing terms by wildly hopeful salesmen. Secretly, I was glad that picture phone had not yet arrived; it was really too early in the morning to have to face such enthusiasm. I am getting old.

"The answer," I said calmly, "is Yes and No. And perhaps Maybe."

"What do you mean?" Fred asked, as I thought he might.

"I have watched the triumphal announcement of various versions of picture phone for forty years, and it ain't here yet. But if we are going to be permitted to dial up bit streams at 64 Kb/s, or some multiple thereof, with bit and byte integrity from end to end, those bit streams don't actually care what they represent. Bits can represent voice amplitudes encoded via PCM, ASCII characters, computer graphics, or whatever. The problem, of course, is getting whatever signal you have to fit the bits available."

"But that's what they're doing," Fred said. "Cards in computers, that take the signal from the telephone line and put it on the PC screen."

"You have to go the other way, too," I said. "You have to have a camera to make an image, and something that converts the image into appropriate electrical signals. Ever since Macintosh came out, people have been making little cameras and scanners that capture scenes or graphics, but they sure aren't on a card. At least not on my credit card.

"And there's another problem. Catching a single picture isn't so hard; fax and copiers do it all the time. But catching, sending, receiving and displaying a continuous series of pictures to fool the eye into thinking it is seeing a moving image is something else again. TV takes about 1500 times the bandwidth of a telephone call. Are you willing to pay for 1500 times as much bandwidth just to see my lips move in real time? Believe me, it ain't worth it."

"But don't you think the generation brought up on TV will want see the people they're talking to?"

"Sure," I answered. "TV is the most vivid, important thing in most people's lives, and it's free. As long as it conditions its customers to expect all communications to be free, they'll want picture phone. But the guy who pays the bill may feel differently."

"Ok," Fred shot back. "How will the PBX be affected? Or how will all that affect the PBX? How will the customer's investment be protected when the TV generation demands pictures?"

"I'll write you an article," I said.

The Saga Of Picturephone

After Fred hung up, my mind drifted back 20 years to my last encounter with AT&T's Picturephone. I was still in the RCA corporate telecom group at that time, and AT&T had sent a questionnaire to Sarnoff (I forget whether it was father or son) asking how many Picturephones RCA planned to have by 1975. As with all such studies, it filtered down the line, and ultimately landed on the desk of "Administrator, Telecommunications Planning." Me. My boss was excited as he gave it to me. "Don't you think the generation brought up on TV will want to see the people they're talking to?" he asked.

"Let's talk budget," I responded.

To deal with the questionnaire, I did the only thing I could under the circumstances. I got out the corporate organization chart and counted the number of people above a certain level. I reasoned that, because there was very little that can be done with Picturephone that can't be done without it, Picturephone would be a perc in the first pass. And who gets percs? Three guesses. From such responses to absurd questionnaires is industrial policy built.

Actually, AT&T's Picturephone planning, circa 1970, was rather interesting. Visualized primarily as a business product, it was a natural for the then new 1ESS central office switch and the various 8XX PBXs which used reed switches to provide a hard-wire metallic path from input to output. These matrix paths could easily handle a broad bandwidth, essentially independent of signal format. Further, with copper pairs rather than carrier systems for trunks, similar bandwidth was available between closely spaced switches in metropolitan areas; the classic example was Manhattan, with perhaps 300 central offices and the densest population of executives in the world. Picturephone signals were four wire, and would work easily on two regular customer loops up to a mile long (longer with equalizers). A third pair was used for speech.

The Picturephone signal needed about 1 Mhz of bandwidth; although it transmitted 30 frames of two interlaced fields each, like standard television, it had only about half as many scanning lines and these were appreciably shorter ("portrait" rather than "landscape" aspect ratio). The master plan was to use analog transmission for local connections, taking advantage of the unused bandwidth in copper pairs and space division switching. For long distance, the intention was to use PCM to digitize the 1 Mhz analog signal into a T2 digital signal of about 6.3 Mb/s. This second level of T-carrier multiplexing was the equivalent of 96 voice channels; thus seeing lips move in real time via long distance would be relatively expensive, but hardly as bad as the 1500:1 bandwidth ratio suggested by broadcast TV.

One of the things that may have done Picturephone in was T-Carrier. At the same time that AT&T was planning for Picturephone to be a main source of business, T-carrier was increasing the capacity of voice circuits under the streets of New York and other major cities without having to dig them up. This effectively blocked the possibility of short-haul copper trunks.

Further, the Picturephone people at Bell Labs, after getting started with the 6.3 Mb/s long distance channel, found PCM a convenient way to digitize their signal so that they could provide processing to reduce bandwidth. Between 1971 and 1973, the Bell System Technical Journal was full of incredible articles in unreadable mathematics explaining how to compress a single picture by eliminating the repetition of the same signal for areas of similar appearance, and how to compress a moving picture by (1) only sending changes and (2) by taking advantage of an existing segment of the picture being translated more or less unchanged from one location to another.

These approaches, still being pursued today, allowed the Picturephone picture to be fitted into a T1 channel of 1.544 Mb/s, reducing it to the equivalent of 24 voice channels rather than 96.* This was still more expensive than a single analog voice channel on copper for local calls, and wasn't really much help with long distance, either, because, at that time, analog voice channels on microwave dominated the field. Fiber optics, a decade later, solved this, but by then Picturephone was all but forgotten.

[Footnote: * Standard NTSC television has room for compression, but HDTV, if it ever gets here, will already be so compressed that any further reduction for telephone use will be difficult.]

Some of the initial deficiencies of Picturephone were quickly remedied: additional lenses for close-ups and slide viewing were developed, a little mirror was arranged to pop down to let the camera view a picture on the desk in front of it, and the ability to display data was added. However, a keyboard was never included; thus data on a main-frame computer had to be located via numeric menu selections, and Picturephone could not really be used as a computer terminal. In my opinion, the absence of a keyboard was Picturephone's most serious defect.

The major factor in the demise of Picturephone, however, was a much bigger story in telecommunications: interconnect. Most of us, between 1970 and 1980, were far more interested in buying our own PBXs and seeking viable "other" long distance carriers to save money on voice calls than we were in renting AT&T's high priced Picturephone equipment to make each call cost a lot more. Tom Carter strikes again!

Some Observations On Picturephone

Picturephone is not like TV broadcasting. With TV, you have a very small group of transmitters and (if you expect to make any money) a very large group of receivers. Thus you do everything possible to lower the cost of the receiver, even if it means putting complexity and higher cost into the relatively few transmitters (including the cameras that feed them). With Picturephone, where the ratio of transmitters to receivers is 1:1, you have to rethink the whole thing. In 1970, TV cameras were pretty expensive.

There are other possibilities. For instance, there is no particular reason why the TV raster has to be painted on the tube face with horizontal lines. You lose about 17% of the time it takes to paint one line by having to snap the electron beam back to the other side of the tube to make the next one, and you lose about 6% of the time it takes to send each complete picture by moving the beam up to the top to start the next field. One ingenious approach suggested for Picturephone was to use a round picture with a spiral scan circling out from the center. This had the great advantage of no horizontal retrace, and the beam only had to move half the width of the picture to get back to the center to start the next spiral. I thought this was clever, particularly if you wanted to minimize bandwidth for telephone transmission, but it was never used.

A background item for economic studies of Picturephone was the incredible penetration of conventional TV into American homes by 1970. Costs being what they were, one possibility was to use the TV set already available for the Picturephone display, with a "magic box" to interface the phone line, contain the camera and coding equipment, etc. AT&T moved in this direction, modifying its Picturephone display to match that of standard TV in 1975.

Today, something quite similar is present: the penetration of the personal computer into the business market. The PC allows today's generation of picture phone designers to ride in on the capabilities of a much more powerful hardware base. Further, the impending ISDN, with its promise of digital channels as needed on a dial-up basis, simplifies both local and long-distance connections. In the 1970s, everybody missed a great chance to take full advantage of TV sets already in place for something more than entertainment. Can we do the same thing today with PCs, or is the situation different?

TV Possibilities in the 1970s

In a world where Video Display Terminals (VDTs) were new, very expensive, and struggling to replace teletypewriters renting for north of $100 a month, the ubiquitous TV set could have been the basis for an incredible revolution. For instance, an interface to the phone line, a little memory, a keyboard, and a means for modulating a signal up to a TV channel would have turned the TV into a dumb terminal for accessing main-frame computers, just when time sharing was getting the same kind of press that ISDN is today. Obviously, such a terminal could be used for computing, but it would have been far more valuable for accessing data bases. Economically, such an approach could have opened up the office market for TV sets and the home market for add-on sales of the keyboard unit. I saw a prototype, designed to retail for about $100, but it never made it to market. Had it done so, it could also have been used for peer-to-peer text communication, a particular need of the hard of hearing, but also something that the rest of us could have enjoyed as well.

A related information approach, using one-way TV broadcasting rather than two-way dial-up telephone connections, is worth mentioning at this point. In 1973, the then Bureau of Standards announced a way of putting a time signal on one of the unused picture lines in the interval between TV fields. A little box could then decode this signal and make the exact time appear on the TV screen at the push of a button. Clearly, this precise time signal had greater value prior to the random use of satellites for TV distribution (with their 0.6 second delay) than it does today, but extension of TvTIME led to "closed caption" text presentations for the hard of hearing.

Unfortunately, the highly competitive market for TV sets makes mandatory the need to hold prices down. As a direct result, the availability of closed captioning has been greatly limited. There is a move afoot to pass regulations requiring closed captioning to be built into all new TV sets at some time in the future; this regulatory approach has worked in the past with UHF tuners, FM on radios costing more than a minimum amount, etc., and just might work here. But there are other unused lines available during retrace which can present news, stock prices, etc. Originally called "teletext," this kind of information would be useful to everybody. Imagine the convenience of knowing the baseball score whether the play by play crew wanted to tell you or not! If closed caption regulation is passed, let's hope it includes the possibility of teletext as well.

When the one-way teletext systems of the mid-70s added a "frame-grabber," they simulated the interactive operation of a two-way terminal connected via telephone to a data base. The general idea here is to keep cycling a vast quantity of information past the TV or CATV customer all the time, allowing his magic box, into which the identify of the desired frame has been inserted, to grab that frame as it goes by and display it until a different frame is requested. In cable TV systems, where a whole 6 Mhz channel could be devoted to such information instead of just a few retrace lines in each frame, a really impressive information utility might have been possible fifteen years ago, and might still be possible today. Fig. 1 is a block diagram of a home information system that could be quite useful, even without the Picturephone unit.

In 1975, a magic box connected to the telephone and the TV and provided with a full QWERTY keyboard could have easily started an information revolution, increasing the capabilities of both TV broadcasting and telephone access to computers and data bases. But somehow, the whole opportunity faded away without ever quite achieving anything. Using enormous subsidies, some foreign governments (notably France with its ANTIOPE electronic telephone directory) have scratched the surface, but so far, nobody has made much money out of some nifty technology.

PC Possibilities in the 1990s.

Today, the PC is in a position analogous to the TV set in 1970. It has penetrated the market to a significant extent, and can act as a "platform" on which to erect a variety of structures. However, with a modem it can already perform all of the Viewdata terminal functions that might have made the Picturephone more useful, even though it does so at about 10 time the cost of a simple magic box and keyboard attached to a TV; its principal justification is its ability to run complex software such as word processing and spread sheets, unknown until the very end of the 1970s. Considering how many people choose NOT to employ terminal functions (Citicorp is planning to provide its own specialized telephone set with terminal features built in for electronic banking, stock quotes, etc.), one cannot help but wonder if the PC has any chance at all of becoming a picture phone terminal, no matter how clever various designers may be in providing add-on capability.

The main reason that some version of video by phone may catch on is not so much the possibility of using the computer as a display as the imminence of digital transmission channels at phone-call prices. With or without ISDN, several channels at 56 or 64 Kb/s can carry a reasonable full-motion picture; whether the processing power to prepare the picture for transmission and to unscramble it at the far end for presentation is part of the PC or not is up for grabs. Designers are, indeed, making boards to fit into option slots; their cost, however, seems to be about the same as some of the computers themselves. How many will be willing to double the cost of their computers for the possibility of a one-on-one picture phone function when fax and other approaches are so readily available and more general in application?

Indeed, further developments in graphic scanners for use with desktop publishing might allow the largely unused computing power of the 32 bit PCs with multi-megabyte memories now coming on the market to do picture phone by simply running the sophisticated software already developed. Something ought to exercise these monsters; I am told that MS DOS 4.0 is still a 16 bit system, and half the processing power of the new chips is spinning its wheels playing with unused zeros. If the boards accessing the digital transmission facilities can be greatly simplified and reduced in cost by allowing the PC itself to do most of the processing, one-on-one picture phone might have a chance.

The alternative to one-on-one picture phone is teleconferencing, tying together two or more conference rooms and allowing groups of scattered people to use the technology to improve their interactive potential. Here is where the main action seems to be taking place at present: complete units including cameras, processing equipment, displays, etc., are being prepared to provide just this function. Portable, these units can be rolled from one class room, conference room or board room to another, as needed. When they plug into 56 or 64 Kb/s channels and dial up similar meeting rooms at the far end, as with a number of private networks today, they may be cost justified and quite useful.

Conferences with distant people seem to have a sort of hierarchy of technology needs: the simplest require just a voice connection. Next, slow scan TV is quite adequate to show slides, flip-charts, and still pictures. Full motion video comes next. At the top of the pile, one has to travel to the remote location in person. Although it is totally unreasonable, we may never be able to get people to use a teleconference rather than fly across the country, and the small progress we have made in getting them to use slow-scan TV will be wiped out with the coming of full-motion TV, in spite of costs.

Audio connections will continue to be used one-on-one, but there is such a difference between these calls and calls involving a number of people at each end that it seems unlikely that even full-motion video will be tempting by comparison. Picturephone was an unsuccessful gimmick in 1970, and its utility hasn't improved in the interim. Further, many competing technologies, unknown in 1970, are now readily available, offer more and cost less. Thus it would seem that some major change in the way people communicate will have to take place before the PC will be accepted as an adjunct to bring picture phone to the one-on-one telephone conversation.

Some Thoughts On Costs

Even with analog technology, a slow-scan TV picture can be sent in about 6 seconds. This will drop to less than one second when 56 or 64 Kb/s channels are available. Clearly, if we don't have to present the illusion of motion to distant eyeballs, the slow-scan picture can share the voice channel between conference rooms, changing pictures whenever a speaker pauses to draw a breath. This "alternate voice-data" approach, eliminating the cost of picture transmission, has to be a major plus. Further, a slow-scan unit for conference room use, complete with camera and display, costs about half the present price of a full motion codec alone ($10K vs. $20K).

On top of this, most full motion video today needs two or more channels at 56 or 64 Kb/s to work. To keep costs down, audio is built into the video channel, typically using ADPCM at 16 or 32 Kb/s. Clearly, one needs at least two DS0 channels at a minimum if any bits are to be left for the video, a signal which is vastly more complex than voice to begin with. No matter how you slice it, full motion video is going to be twice as expensive as slow-scan; in a world where customers will switch long distance carriers for a saving of 1.5% per minute, how much will they be wiling to pay to see lips move in real time, or even to see pictures at all?

Via The PBX.

So how will our new digital PBXs (and CO Centrex switches) deal with all this? It is quite evident that anything that will fit into a single 64 Kb/s channel can be handled quite easily on most PBXs today, and if these 64 Kb/s channels are compatible with ISDN's PRI, local and long distance connections can be set up for pictures as easily as for voice. However, as we learned in Jon Zingman's article in the June 1990 Business Communications Review, new teleconferencing standards are being developed to take advantage of channels broader than a single DS0 channel. And this is where the plot thickens. Any communication switch, PBX or CO, will have to have the capability of establishing connections that include the equivalent of several DS0s; further, we can count on a variety of other functions besides video teleconferencing to use these channels, once they become available.

The first step is the use of 2 DS0 channels, as discussed above. This is easy enough as two separate channels, but one might hope that a Basic Rate Interface could be arranged to combine its two B channels into a "broadband" connection in the not too distant future. Most proprietary PBX telephones use the equivalent of two B channels and a signaling channel; however, one B channel is reserved for voice and the other for data, making this approach difficult. It would be a convenience if the line card for digital phones, often using a single pair to each work-space, could be used for either a 2DS0 video channel or a voice-data phone, depending on what was plugged in.

The next step is the H0 channel, the equivalent of 6 DS0 channels, or 384 Kb/s, followed by nH0 to provide broader bandwidths. Note that 6 is a factor of both 24 and 30, and the next named channels are H10 and H11, at 1.536 (4H0) and 1.920 Mb/s (5H0). These are the equivalent of a US and European T-span, respectively, excluding sync bits in the former and the two additional channels in the latter used for sync and signaling. Switches should, in principle, be able to gather together and interconnect such broadband channels.

I talked to AT&T, Northern Telecom and Rolm, and found none of these companies is as yet prepared to talk about H0 or nH0 interfaces. However, they all pointed out that there is no problem making two or three B channel connections in parallel, and one H0 channel can easily be constructed from six parallel connections from three proprietary or BRI interfaces of 2 B channels each. The PBX people seem to be looking for some indication that there is a multi-channel market for them to serve. Manufacturers of teleconferencing equipment, however, while willing to use PBX switched connections, can also use T1 multiplexers and similar gear to carry their signals. One might hope that PBX designers will act more quickly and effectively than they did with non-modem data and not turn video teleconferencing over to others as they gave data away to the LANs.

Internal to digital PBXs, there are two principle architectures dominating the field today. The first, exemplified by Northern Telecom, Siemens, Harris, Mitel, etc., switches individual DS0 channels in a central switch. Each DS0 channel represents one time slot out of 32 multiplexed onto a serial path to and from the central switch. At the central switch, the talking party's signal is first changed to the listening party's time slot, and then a space connection is established between the incoming serial path from the talker to the outgoing serial path to the listener in that time slot. Evidently, the use of several connections at the same time is possible, but now the traffic handling capacity of the matrix is altered when one connection needs more than one path through the switch. With only a limited portion of the switch bandwidth available to any given port card, care would have to be taken in setting up broadband channels.        The second architecture, as seen in Rolm's ROLMbus 295 and AT&T's System 75, uses a backplane bus for the switching mechanism and makes connections by connecting A's talk path and B's listen path to the bus in one time slot for A to B, and B's talk to A's listen in a different time slot for B to A. Here, at least in single modules, the entire bandwidth of the switch is available at any port, and several time slots in each direction can be assigned to a given connection with somewhat greater freedom than in systems where only a small part of the bandwidth is available at any port.

If a market for nDS0 or H0 channels should open up, Northern Telecom's increase in the number of serial links available from each line group to the central switch, part of the Meridian 1 development, will be an advantage. Similarly Mitel, with a single serial link of 32 time slots to each physical card slot, usually serving only 8 devices, has extra time slots available from which to build broader channels. In smaller sizes, System 75 or a single module Definity Generic One, with all its time slots available at all card slots, will be able to build broader channels. In larger sizes, however, its 512 8-bit one-way time slots may be too few to permit multiple timeslot connections without seriously degrading traffic.

Rolm, with the 9751, would seem to be in the best position to offer H0 channels, should it decide to do so. ROLMbus 295 has about 1500 16-bit one-way time slots available in each module, although each shelf bus is appreciably more limited. However, as a result of converting to conventional 8-bit coding from the 12 bit coding used prior to the 9751, Rolm has, for all practical purposes, twice as many time slots if the 16 bit bus is thought of as two 8-bit buses. If 8 bits were used for conventional voice and circuit-switched data, the other 8 bits could be used for "concatenated" connections (several sequential time slots used as a group) which could provide H0 circuit switched paths, high speed packet bursts, etc. Although Rolm's early success with non-modem data was based on sub-multiplexing its bus (assigning separate data connections only the bit rate needed, permitting a one-way voice time slot at 192 Kb/s to handle a lot of data), super-multiplexing was also available using several adjacent time slots in the bus for data at much higher speeds. All this technology is tested and will be available when a market open up.

It should also be noted that ROLMlink, from line card to work-space, uses only a single pair for a control channel and three rather than two 64 Kb/s B-like channels. Although the third channel is presently unused, a new line card could easily be designed to include it, and a line card handling 8 pairs could support 4 H0 channels. This will be much more difficult with ISDN BRI connections which need two pairs each. It would take the equivalent of 12 BRI-like ports to support 4 H0 channels, and each H0 channel would need 6 rather than 2 pairs between line card and work space.

Northern Telecom's Video Test Bed

Because so much related to video teleconferencing today represents hopes and projections rather than actual accomplishments, Northern Telecom is building its own in-house video network. Using standard T-spans and its Meridian PBXs, Northern hopes to gain hands-on experience with video conferencing while establishing a demonstration vehicle to try out new ideas from customers and to demonstrate what can actually be done.

So far, Northern is sticking with two channels of 56 Kb/s each for a video-audio connection (although when 64 Kb/s channels and standards are available, the extra bandwidth will be most welcome), using proprietary codecs from three different manufacturers: CLI, PictureTel, and Video Telecom. Rob Preece, who is in charge of the project, reports marked improvements in picture quality in the last several years, and seems quite enthused by what he has been able to do so far.

All three codec manufacturers provide two separate physical outputs, and use a packetized format (even in a circuit-switched environment) so that headers are available at the receiver to put signals coming in on different paths in the right order, and to provide some forward error correction (there is no time for retransmission in case of error, and the coded signal is so compact that there is no redundancy left as there is with PCM-coded speech). From PBX to conference room, two data connections at 56 Kb/s each are used between data line cards and high-speed data interfaces. The voice-data capability of Meridian digital phones and their line cards is NOT employed. Each end-to-end connection is set up (separately at present) using speed calling.

Video teleconferences are not limited to connections between two conference rooms. Several multi-point bridges are being tested to give experience with different ways of deciding which conference room sees what. Various algorithms include who is talking the loudest and how long it has been since the picture last changed; in educational presentations, chairman control is another approach.

In Canada, some slow-scan TV is being used, apparently with great success, among various technical groups. Whether slow-scan or full motion, Northern Telecom is learning how teleconferencing works the only way anybody can: by actually doing it. This experiment will be well worth watching over the next few years.

Summary

If I had been doing it, I would have been strongly tempted to keep voice and pictures separate. In that way, a voice connection between two conference rooms or two individuals could be established as usual, and pictures added as needed. Using alternate voice-data capability on this path, slow-scan TV at 64 Kb/s, perhaps little more than a program running on a PC with the right kind of graphics scanner, could provide high quality still pictures with no additional transmission cost. If moving pictures had to be added, even a single B channel, no longer burdened with voice, might be able to hold full-motion video, but would almost certainly have to have its own specialized processor.

The people who are actually getting the job done are packaging audio and video together, and are including displays based on frame grabbers to handle still pictures. If they continue to make progress at the present rate, we can count on video teleconferencing between conference rooms to increase in popularity. One-on-one picture phone, however, is something else again. Northern Telecom considers it a niche market, and is busily looking for the niche. But an answer is still needed to "What can we do WITH a picture phone connection that we cannot do WITHOUT one?"

Alternatives

It should be kept in mind that the technology that makes all this possible can, in some instances, also make it unnecessary. Let me illustrate by describing one of my greatest inventions: picture phone with NO bandwidth required for the pictures.

While I was filling out the AT&T Picturephone questionnaire for RCA, I was also reading about one of RCA's early Selectavision concepts. This version was going to make holographic recordings of TV pictures for laser playback; the advantages were that tapes could be produced by pressing, sort of like a very long phonograph record, and holographic imaging meant that surface scratches, holes or whatever would not harm the quality of the reproduced picture; you could run the tape back and forth as often as you liked, but no matter how scratched it got, picture quality would not be affected.

Broadcast TV has 30 complete pictures (frames) per second, 1800 per minute, or 108,000 per hour. If each could be a still picture, a one-hour tape could hold photos of 100,000 separate individuals. My picture phone idea was to have the picture from each person's security badge sent to a central location where a tape could be made with an index track based on social security numbers. Then, if each person on the network had a Selectavision player and this tape, a phone call could be a lot more fun. I would call you, give your player my SS number using DTMF, and it would pop up my photo for you to look at. You could extend the same courtesy to me. And then, when we met in O'Hare airport, we would be able to recognize each other.

My management didn't like the idea, but I still think it's a great way to use visual communications. Suppose you and I are in different locations, but we have to discuss a document or engineering diagram. If we each have the same document on our own CD ROM, we can both view it as we talk, no picture transmission required.

Oh, well. It's just a thought. Everybody wants to be in the movies. When we can be a movie star in our next conference, or even our next telephone call, who cares about bandwidth?

SIDEBAR: Some pertinent numbers concerning displays.

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Copyright 2006 Lee Goeller. All Rights Reserved.