On-the-road productivity makes a low-cost advance with the arrival of a clever new fax device. With the machine installed in a small-business home office, an executive can dial in from any remote fax site and -- much as he or she would summon messages from a telephone-answering device -- instruct the central machine to relay faxes that were sent to the home number.

One businessperson who's dialing thus is Barry Lewison, co-owner of Quota Phone, a $2-million discount-shopping wholesaler in Harrison, N.Y. Merchandised to associations and businesses, Quota Phone's packaged product is sales intensive, with deals often worked out via fax exchanges that would normally keep Lewison chained to a desk. He grabbed a fax-on-demand unit as soon as such products hit the market.

Now when he's away, Lewison punches codes into a keypad, and exact doubles of the faxes addressed to his home office come streaming in on the remote machine. Recently, he sustained a lengthy negotiation, ironing out the fine print of a complex contract, from whistle-stops on the road. Marvels Lewison, whose six-person office otherwise shuts down at 5:30: "It's like keeping the business open 24 hours a day."

The new varieties act also as telephone answerers and boast such advanced features as 50-page memories and automatic beeper alerts. Among the entrants: Brother Intellifax 780MC, listed at $949 (call 908-356-8880); EMI SmarterFax Mailbox Manager, $699 (call 214-340-6789); and Macronix Vomax 2000, $499 (call 408-453-8088).

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