From: Matthew J Ghio <mg5n+@andrew.cmu.edu>
Date: Sun, 10 Oct 93 11:39:46 PDT
To: cypherpunks@toad.com
Subject: Re: PHONE PRIVACY: real-time billing with digital postage
In-Reply-To: <9310100621.AA08523@netcom5.netcom.com>
Message-ID: <cgi5NbC00awT8CglBU@andrew.cmu.edu>
MIME-Version: 1.0
Content-Type: text/plain


Nick Szabo <szabo@netcom.com> writes:

> Scenario: long distance company receives a call from one of its
> customer phones.  It doesn't know which phone, only that the
> phone's local service area provider is requesting a connection.  It
> notes the area code/country to and from to determine the rate, and
> receives the proper digital postage payment from the calling phone.
> It notes the destination phone number only in order to pass it on and
> complete the circuit.  The long distance provider doesn't know
> the caller's phone number and doesn't keep a permanent record of the
> other information.

It's been tried before.  That's how calling cards worked in the mid
1980's.  The long distance company had no idea where the call was coming
from when it went into their credit card port.  It didn't take the
hackers long to figure out how to exploit the anonimnity of that system!
 Now all credit card calls are automatically traced.

I like the billing indicator on a LED on the phone tho...  It would be
easy to implement too.  Right after the call was dialed, the phone
company could send a short tone to indicate the cost per minute, which
would be interpreted by a microchip in the display.  When the receiving
party answered, a second connect tone (or even a click by change in
voltage) could signal the indicator to start counting time...  The call
would still be billed at the end of the month, but at least you could
see what your phone bill would be before you got it.