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From: essachs@ihuxl.UUCP (Ed Sachs)
Newsgroups: net.followup
Subject: Re: Fraudulent use of AT&T Calling Cards
Message-ID: <1143@ihuxl.UUCP>
Date: Fri, 25-May-84 08:52:36 EDT
Article-I.D.: ihuxl.1143
Posted: Fri May 25 08:52:36 1984
Date-Received: Thu, 31-May-84 20:24:37 EDT
References: <3004@brl-tgr.ARPA>
Organization: AT&T Bell Labs, Naperville, IL
Lines: 21

====================================================
Credit limits sound like a good idea, but they are far from
trivial to implement.  The machines which do the credit card
validation and billing (NCP and TSPS, for those familiar with
AT&T hardware) generate only individual charging records
for individual calls, which are sent daily (or perhaps less
frequently) to accounting computers via tape or data links.
Thus, they have no knowledge of how much is charged, or the
balance outstanding, on an individual account.

An interface back from the accounting computers to NCP (where
the "valid calling card" database is kept) could be created to
cut off calling cards with balances over their preassigned limit,
but there would be a minimum of several days turnaround (assuming also
that the outstanding balance per account is computed more
frequently than once a month, which I doubt).
-- 
				Ed Sachs
				AT&T Bell Laboratories
				Naperville, IL
				ihuxl!essachs