(FORTUNE Magazine) – The hottest weapon in the cutthroat battle among supermarkets is the fax machine. Chains across the U.S. -- from Simon David in Dallas to Roth's Foodliner in Salem, Oregon -- have installed fax machines in their stores so that customers can transmit their grocery lists. Supermarket employees take the selected items off the shelves or from a warehouse and deliver the order for an average charge of $10. Not everybody has a home fax machine, of course. To reach such have-nots, King Soopers, a chain of 66 stores in the Denver area, operates a telephone bank that takes orders 24 hours a day, seven days a week. The orders are faxed to the supermarket closest to the customer's home. The charge: $9 for delivery, $5 for pickup at the store. Donald Gallegos, president of King Soopers, which is owned by Cincinnati's Kroger, says response has been good, and he thinks it will get even better: ''When it gets to be wintertime, a lot of people will be shopping by fax.'' - M.A.