textfiles/hacking/debtcard.txt

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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.