Vendors demonstrated six flat-panel monitors with the new interface on board at the working group's technology showcase. And at an Intel "fashion show" of small form-factor computers, all of the exhibited machines' motherboards had DDWG's built-in digital visual interface (DVI).

"We got the analog off of those motherboards, said Steve Spina, strategic initiative manager for graphics at the desktop products group of Intel (Santa Clara, Calif.). "The common goal of the DDWG is the eventual removal of analog altogether. Analog is the next thing on the legacy-removal road map."

Hammered out in just about five months, DVI has two noteworthy cornerstones: no options and no royalties. "We really didn't want any options [like USB and IEEE 1394] in this," said Scott Macomber, president of Silicon Image Inc. (Cupertino, Calif.), which supplies the transmission minimized differential signaling transceivers on which DVI is based. "That's part of what caused the confusion and the split" between two earlier digital-interface efforts: the 20-pin connector proposed by the Digital Flat Panel initiative and the Video Electronic Standards Association's Plug & Display interface, which uses a 30-pin connector. A format war between those initiatives broke out last summer. The Digital Display Working Group was formed in the fall to hammer out a "convergence spec" acceptable to the PC, graphics and monitor industries.

Spina said DVI had to be made sufficiently "robust and complete to ensure complete interoperability and [to ensure that], if there are any patents in there, you won't get sued."

The working group — comprising Intel, Compaq, IBM, Hewlett-Packard, Fujitsu, Microsoft, NEC, Dell and Silicon Image — delivered a Version 0.9 spec to the forum. The complete technical specification offers a blueprint for building compatible products, covering architecture, protocols and the electrical and mechanical interfaces.

"In order to make sure we can have compatible products built, we need to put [the spec] out for industry review to tell us where it may need clarification," Spina said. Hence the 0.9 designation.

The working group has settled on a single connector that supports several flavors of DVI: digital only and digital plus high-performance analog, for example, with the digital section the same for both versions. It also handles single- and dual-channel operation, the former for formats up to 1,600- x 1,200-pixel UXGA and the latter for higher pixel counts.

"It needs to be easy for consumers," Macomber said, defining "easy" thus: "If the connector plugs in, it works, and whatever features are there are going to work."

The DDWG group acknowledges that analog will remain a transitional requirement. "We realized as a group that there are probably two markets," said Spina: "systems that can't get that 15-pin analog connector off the back of the box in a hurry, so they'll want digital only, and bundled systems — say, in niche workstation markets — where they can transition [to DVI] very quickly, going to a single integrated connector and then eventually getting rid of the analog."

Allen Alley, president and chief executive officer of Pixelworks Inc. (Tualatin, Ore.), a display-controller chip company, believes "the smoothest possible transition will be to introduce digital displays alongside analog displays. This allows customers to dictate the pace of adoption for the new digital interface.

"As an industry, we must work together to avoid forcing end users to choose between analog and digital, which could inhibit adoption of flat-panel display technology altogether," Alley said. "We foresee demand for both analog- and digital-interface monitors continuing to expand for a minimum of three years."

Next frontier: CRTs
Compatible products at the Digital Display Working Group pavilion included a range of monitors with flat-panel displays: a 25-inch plasma monitor from Fujitsu; a 42-inch plasma monitor and a 15-inch LCD monitor, both from Philips; 18-inch LCD monitors from IBM and Compaq; and a Silicon Graphics 17.3-inch wide-screen monitor, driven by a graphics board from Number Nine Visual Technology Corp.

Intel and Silicon Image also demonstrated what Spina called "the first early lab version" of a digital-input CRT.

The dual-channel configuration of DVI was defined "to support future bandwidth requirements," Macomber said, "but we weren't thinking about LCD monitors or plasma monitors in particular." In fact, the DDWG group was thinking about CRTs — which, unlike most flat panels, are basically analog displays.

"Of course, it makes sense to keep things digital as long as possible, but the real opportunity is more than just doing the D/A conversion in the monitor," Macomber said. "Now that there's a viable digital interface standard, you can think about redoing all of the electronics, simplifying the monitor manufacture and design, and lowering the overall costs. You might be able to take out multisync, for example, which is expensive to put in and to test and has a lot of complications associated with it."

Spina emphasized that the working group strove for display independence. "There were 77 million analog [input] CRTs shipped last year," he said. "In the next six months, we'll look at how to enable that industry to move [to digital input] as well."