Digitran, a Great Neck, N.Y., company, is building an alternative network for lower-cost facsimile transmission. Using proprietary technology, the venture-backed start-up digitizes signals over leased phone lines to move more data in less time. Its long-distance fax service is offered in Washington, D.C., and New York City for 25% less than other carriers'. Chairman and cofounder Martin Ellis sees a lucrative market among frequent faxers, especially law and accounting firms. He expects to link Chicago and Los Angeles to the network this month. -- Anne Murphy