ISDN HARVARD MEDICAL SCHOOL INSTALLS ISDN-BASED DEBIT CARD SYSTEM Students pay up front, then monitor accounts during the school year Harvard University Medical School in Boston is living proof that we have come a long way from lunch tickets. The prestigious school is using a simple but efficient ISDN-based debit card system that allows students to eat with a swipe of plastic. The current debit card system is actually an enhanced successor to an earlier paper-based system that also allowed students to pay for meals ahead of time. However, this predecessor system required students to present paper coupons when entering one of the two medical school cafeterias. The thousands of paper coupons were then sent to the Vanderbilt Hall Student Services Group, where, at the end of each month, they were manually tabulated so student and food vendor accounts could be updated. The idea was good, but the execution was labor-intensive and lacked efficiency. Yvonne Geeve is general manager of Harvard Medical School's Vanderbilt Hall, the Housing and Residence Life Center on campus which administers the program. She worked with the old system and greatly prefers the new version. She believes students feel the same way. "Students carry the cards instead of coupons or cash, and they can keep daily track of their accounts," she notes. "They spend the money up front for making purchases around campus or for using services on campus, and at the end of the year they have an account of what they used. They are also able to receive a refund for unused services." In an effort to update the old system, Harvard contracted with Griffin Technologies, which installed a debit card system that called for a card reader at each of the cafeterias and a small mainframe computer at Vanderbilt Hall. Now, instead of submitting the paper coupons, student diners merely swipe their debit cards through the card readers, which query the nearby mainframe concerning the account in question. If the account is paid up, then the mainframe flashes an approval along with current account information back to the cardreader in a visual readout. The student's purchase is then approved. New England Telephone helped enable the system by adding an RS-232 connection to the card readers, converting the transactions to packet data and then routing them via permanent virtual circuits over a "D" channel of Harvard Medical School's existing voice-based ISDN network. Actually, the application only requires 2,400 bps worth of bandwidth on a 9,600 bps channel. Because redundancy was built into the system, all cafeterias may transmit simultaneously over separate circuits. And because the "D" channel is not fully utilized, there is enough remaining bandwidth to retain that redundancy, even if more locations are added. This technical work was accomplished in a day. It took about two more weeks for Griffin Technologies _ working with the New England Telephone Data Technical Support Group _ to develop compatible hardware and software for the Vanderbilt Hall mainframe. This service, although not technologically complex, underscores the flexibility of ISDN. In this case, it allowed packet data to be transmitted over a voice network. Harvard has also used ISDN for video conferencing. The success of the debit card system has encouraged Harvard to consider deploying it throughout the university's main campus in Cambridge. Beyond that, other possible future applications include using the debit card for entry to restricted areas, as well as for vending, laundry and entertainment services.