Classic Computer Magazine Archive COMPUTE! ISSUE 145 / OCTOBER 1992 / PAGE 48

When data worlds collide. (video telephone)
by Troy Tucker

This month I'm going to step off the beaten trail and into an area of communications that, for the moment, doesn't involve online services. Imagine a device that incorporates the telephone, television, and personal computer into a single unit. If this device existed, it would revolutionize the communications industry. You could carry on visual telephone conversations, watch television, and interact with a graphical database all at the same time! Well, it's here--sort of.

Ever hear of a VideoPhone 2500? AT&T unveiled its creation on January 6 this year. It's not the supercomputer that l described earlier, but it has the potential of becoming just that. The VideoPhone 2500 is a full-color, full-motion videophone that uses standard phone lines to transmit voice and video data. While this may be old news to you, I think it deserves a second look.

First of all, the videophone carries a $1,499 price tag. While that may seem a bit inflated and beyond the means of the average consumer, the videophone is packed with some sophisticated hardware. It contains a superfast 19.2Kbps (kilobits per second) Paradyne modern that is used to transmit compressed voice and image data. A 3.3-inch color LCD displays the images, and a color video camera captures them for transmission. Both are mounted in a single unit on a swivel base. It looks a little like a Nintendo Gameboy mounted on an ordinary telephone. Adjustments can be made to the camera's focal point, the display's brightness and contrast, and the frame rate. Should you receive a call when your appearance is less than perfect, you can turn off the video transmit so the caller can't see you.

Video data can be transmitted at a maximum of 10 frames per second. If you know anything about video, then you know that this isn't a flicker-free system. Television operates at about 30 frames

and movies operate at 24 frames per second. Certain settings allow you to trade resolution for motion, but the maximum output is 10 frames per second.

In order for the videophone to send and receive voice and image data, it must first compress it. AT&T gave this job to Compression Labs (San Jose, California). Compression Labs is currently working on a video conferencing peripheral, Cameo Personal Video System Model 2001, targeted for the Macintosh and PC and compatibles. The Cameo requires a special digital ISDN (Integrated Service Digital Network) line, but it can transmit up to 15 frames per second at 128 x 112 resolution.

The ISDN is an international plan to install totally digital phone lines. Once implemented, ISDN will offer better reliability and throughput using digital channels that can handle much higher speeds than voice circuits. The ISDN will allow users to connect to computers, fax machines, telephones, and other communications devices. Voice, data, and video will travel simultaneously over the same digital lines. The ISDN could be a communications revelation that would serve as a catalyst for many new hardware and software developments.

Of course, switching over to this advanced service isn't going to happen overnight--that is, if the phone companies have anything to say about it. They have a lot of old switching equipment in operation.

They're not just going to pull the plug and junk it. There are many other problems to consider, too. Do you know what happens when the power goes down when you're using a digital phone service? No more phones. If you plan on taking advantage of an ISDN line, you must have an expensive device called a PCISDN, which makes the connection. Also, all household (analog) telephones will be worthless on an ISDN. Another headache will be connecting computers to digital networks. It may be difficult to produce an internal adapter. And I've just scratched the surface. There will undoubtedly be many other stumbling blocks in getting this service active nationwide.

When the ISDN is available, businesses will probably be the first to take advantage of it. Digital PBX systems are already in place; they just aren't used to their full potential at present. AT&T is working on a prototype for the home that will convert analog to digital. This, hopefully, will ease some of the consumer's financial burden when the switchover takes place. No matter how the ISDN service is implemented, it will be slow and painful. But when it finally is in place, we're sure to see some pretty amazing things.

Speaking of amazing things, by the time you read this, COMPUTE/NETwiII be going through some remarkable changes. Operating under the auspices of PowerVision, COMPUTE will be a major part of the first 9600-bps online service aimed at consumers. You'll find games, software downloads, graphics, and information galore, to say nothing of the one-to-one interaction with editors and computer enthusiasts. Look for more coverage of this change in future issues of COMPUTE. In the meantime, I'll see you online!