Digital Monitor Market Divided on Signaling Scheme

by David Lieberman

EETimes, September 28, 1998 - Silicon Graphics Inc. and three development partners will roll out a wide-screen LCD monitor this week that will open a new front in the battle to define a standard digital interface for flat-panel monitors. The product, which serves as a launch vehicle for a new SGI business in PC monitors, adopts the low-voltage differential signaling (LVDS) interface, as opposed to the transmission-minimized differential signaling (TMDS) schemes that are the focus of a standards effort among PC makers.

The rollout by SGI and its partners accompanies the public emergence of a consortium to promote LVDS — the Visual Interface Consortium International (VICI) — and comes just two weeks after Intel Corp. announced the formation of the Digital Display Working Group to bring order to a TMDS world awash in standards proposals. Hope for a universal digital-interface standard for flat-panel monitors thus seems increasingly remote, making the ability to mix and match computers and monitors an ever-more elusive goal.

"Vini, vidi, vici," Julius Caesar said: "I came, I saw, I conquered." The LVDS technology of National Semiconductor Corp. (Santa Clara, Calif.) and Texas Instruments Inc. (Dallas) may have conquered the notebook-computer world, but it has met resistance in its quest for desktop-monitor applications. Here, the Video Electronics Standards Association (VESA) has based its standards on the TMDS technology that Silicon Image Inc. (Cupertino, Calif.) used in its PanelLink transceivers.

VICI's existence had been rumored since June, when word broke that a group was being formed to standardize an LVDS-based spec informally called the Digital Monitor Interface. The effort is an outgrowth of SGI's collaboration with National on specifying a second-generation of LVDS called the LVDS Display Interface (LDI), plus its codevelopment of the new monitor with Mitsubishi Electronics America Inc. (Sunnyvale, Calif.) and its cooperation with Number Nine Visual Technology Corp. (Lexington, Mass.) on compatible graphics boards for the PC and Mac.

The LDI heightens performance, incorporating a dual-pixel mode that extends its capabilities to high-definition TV and beyond, while adding a number of TMDS-like features to the technology. The moniker OpenLDI has also been applied to the VICI effort along the way.

The Digital Display Working Group, meanwhile, is a fast-track entity whose immediate goal is to break through the confusion caused by the proliferation of TMDS standards: Plug and Display (P&D), developed by VESA, and Digital Flat Panel (DFP), developed by Compaq Computer Corp. and ATI Technologies and now in a VESA working group. The emergence of VICI may indeed gum up the works.

But the explosion of digital interfaces may merely be growing pains that will not adversely affect the market long-term.

"If it were late in the year 2000, I'd be pretty negative," said Dataquest Inc. analyst Martin Reynolds. "But having all these standards is okay for the coming year to year and a half, as people prime the market by getting technology out there.  "When we really start seeing volume on these things, which is still a couple of years away, we should start seeing some absolute standards," he said. "And then everybody will migrate to them in a generational shift."

Besides the collaborators in the new monitor, the VICI group includes Texas Instruments.  Mitch Abbey, marketing manager at National's Interface Product Group, said VICI now consists of "about 15 companies talking together."

Abbey decried what he called the stone wall put up by VESA against LVDS as an alternative monitor standard to TMDS. "They're hell-bent for leather for TMDS, whether it's the right decision or not," he said. "They're still talking about going back into the FPDI-2 notebook standard and redoing it with TMDS, when TMDS has never been used in a notebook and no notebook makers are talking about using it."

Abbey claimed the Digital Interface Standards for Monitors (DISM) group of Japanese manufacturers, which has brought its digital-interface activity under the Japan Electronic Industry Development Association banner, "has been trying to give [VESA] proposals, and [VESA is] trying to block them, saying, 'We don't need another standard.' "

But it's unwise to ignore Asia in digital interface matters, Abbey said. "Ninety-five percent of the displays come from Asia, and almost all of the notebooks — including those from the OEMs in the U.S. — are being built in Taiwan, where most of the desktops are also made. Will OEMs have the clout [to drive a particular digital interface at a time] when they're giving ODMs [outsource design manufacturers] in Taiwan the freedom to design the entire box?"

The Digital Display Working Group recognizes that Asian participants will enhance any digital interface's chances for success. Steve Spina, strategic-initiative manager for graphics at Intel's Desktop Products Group, said a trip to Japan is planned "to get some of those people involved and to work with [Asian] display manufacturers."

The working group's roster already includes Fujitsu and NEC, in addition to Compaq, Dell, Hewlett-Packard, IBM, Intel and Microsoft.