
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.

 
