In the race to mix the World Wide Web and television, progress is measured in terms of how little a consumer device resembles a personal computer. Worldgate Communications believes it's up to the challenge, while giving new meaning to the term "thin client" in the process.
This revolution, in Worldgate's view, is in the dumbing down of the cable set-top box � putting as little circuitry and functionality into the device as possible. Instead, the brains and applications reside on cable network servers. With this setup, Worldgate plans to offer consumers a path to the Internet and access to additional services, including email and chat at high speed � three times the rate of most modems � all through their television sets for only US$4.95 per month.
Worldgate president Hal Krisbergh sees his company's pending service as a significant advance in giving Net surfing broad appeal, doing Network Computer and other devices of its ilk one better.
"I took what [Sun's Scott] McNealy and [Oracle's Larry] Ellison did ... they said the network is the computer. I'm taking it a step further and taking all of the computer out of the home and leaving the dumb box at the television," explained Krisbergh.
But others bringing the Web into home and hearth believe otherwise. "This set-top box can't handle HTML, servers are in the cable network, and it transmits only images," WebTV president Steve Perlman pointed out. "Hal sees this as innovation, but what they've got just doesn't work."
Worldgate is trying to tap into the what is seen throughout the industry as a fertile market � services and devices that break down the vast expanse of the Internet into bite-sized pieces fit for mass consumption. Part of reaching this market is stripping away everything about a computer that makes it daunting � configuring the computer and software, installing applications, and even navigating an operating system to access programs.
In Worldgate's system, the cable network is divided into a number of local area networks. For each local network, a cable provider has a server on which resides all applications for browsing, email, chat, and Internet access. Subscribers get a set-top box which plugs into their televisions or VCRs and can purchase a wireless keyboard. Through this box, customers can, for example, download Web pages, click on links, and receive and send email. The box records URLs and coordinates for Web links and sends them along the cable network to the server, which is always logged on to the Internet via a T1 or T3 connection.
What the set-top box displays on television are only bitmap images of Web pages, although Krisbergh claims his system is completely interactive, allowing unfettered two-way transmission of data.
Just how this transmission works is a complex mix of two different parts of the broadcast band. Rather than pushing aside a cable channel's programming to use its 6 MHz pipe, Worldgate plans to use the vertical blanking interval to download data to homes and the cable sub-band for customers to transmit their keystrokes and pointer device selections.
The VBI is a part of the broadcast signal that appears after a single screen is finished scanning. Broadcasters talk about the VBI in terms of lines � roughly 20 exist, and 11 lines are generally available for use � but it describes the periods of time that the screen is blank during a broadcast.
While invisible to many, the VBI has given broadcasters more elbow room through which they can transmit supplementary material. For example, a part of this signal is dedicated to closed captioning. PBS National Datacast uses the 11 lines available to transmit Web content that producers of programs such as Nova develop to augment the information in their television programming. This supplementary content is transmitted via Wavephore's WaveTop to broadcast-capable PCs, so essentially the VBI is treated as a broadcast signal.
But Worldgate treats the VBI as a bandwidth source. And as a bandwidth source, the VBI looks good � on paper. Each line of the VBI is capable of transmitting data at 19.2 Kbps, and Worldgate is electing to use four additional lines that Krisbergh calls overscan. With a total of 15 lines, Krisbergh, a former cable industry executive, said he has more than enough capacity � 288 Kbps per channel. Worldgate's system is designed to hop between channels to snatch up this capacity. So a 50-channel cable system offers Krisbergh's service a total transmission capacity of around 14 Mbps.
The sub-band that transmits customers' data � keystrokes and mouseclicks � does so at rates between 12-14 Kbps.
"In essence, you have unlimited capacity," Krisbergh said.
Not so, explained a company with a lot of experience in working with the VBI. That company, Intel, developed Intercast, the broadcast-capable card for PCs that has allowed PBS National Datacast, via WaveTop, to transmit its supplementary material to computer users.
By using the VBI as a bandwidth source, the band becomes a shared resource susceptible to the ebb and flow generated by the fluctuation of users on the service. "They're better off throwing out the Martha Stewart channel and getting 30 Mbps � that's living," said Mike Richmond, general manager for broadcast products at Intel.
Worldgate's network allows eight simultaneous sessions per channel. Each channel has 288 Kbps - divide that by eight sessions, and, at most, there is a capacity of 36 Kbps per user when the system is running at full capacity. "This is not a replacement for digital cable or two-way services," Richmond said.
The logistics of getting this system to work puts Worldgate at the mercy of broadcasters, who must develop the supplementary material for his service, and the cable providers, who must agree to offer the keyboard for a low price and install the set-top boxes � the system supports an advanced analog and a digital device � for little or no extra fees. This fact isn't lost on Krisbergh. "I can't tell the cable providers how to sell their services; we can offer only models," he said, conceding that his service might end up costing more than $4.95 per month.
In his defense, Krisbergh points out that it will take time to iron out all the logistics � and to get standards into place for broadcasters to develop materials for his service. That's why Worldgate has sponsored HyperLinking conferences such as the one it hosted this week in Los Angeles, and why it has started a standards body, the North American Channel Hyperlinking Organization, to work out some of these details.
In the meantime, Krisbergh is trying to get his trials of his service off the ground. Originally scheduled to start at the beginning of this summer, Krisbergh elected to delay the testing because of the limits on the resolution. The system had only a CGA resolution (two colors at 640 by 200 pixels), and he wanted to enhance it for richer digital transmission.
Through limited testing � 10 to 15 users in each market of St. Louis, Long Island, and Philadelphia � Krisbergh is confident that his system works. The tests that are about to begin within the next month will see these markets ramp up to between 100 and 200 users, he said. But when asked which cable companies were participating in the tests, Krisbergh was short on specifics: "We have had all sorts of commitments on trials. I just wouldn't put a number down as to who's doing what, when, and where."
Whether Worldgate's system can withstand the weight of a larger numbers of users will, for the meantime, remain a mystery. But Intel's Richmond doesn't fault Worldgate for trying.
"I think their heart is in the right place ... they may be defining a new low-end," he said.
