"I don't see why sales of voice systems can't hit $500 million a year just four years from now," says Jack LeVan, president and CEO of Vocollect ( www.vocollect.com).

What's so notable about that statement is Vocollect's sales this year are expected to be $75 million, and the company accounts for 80% of the market, says LeVan.

On Wall Street, that $500 million claim would be called the whisper number, a figure that exceeds mainstream projections. To LeVan, the next wave of adoption makes it realistic. He sees expansion of voice to third-party hardware not currently using the technology. Many warehouse software companies have recently written direct interfaces for voice. Companies are adopting voice to complement other data management tools. LeVan also cites expansion into specialty retailers, after-market auto parts and pharmaceuticals.