Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!cyclops!csense!bote
From: bote@csense.UUCP (John Boteler)
Newsgroups: sci.electronics
Subject: Re: How to Hack Payphones (?!)
Message-ID: <261@csense.UUCP>
Date: 10 Jun 89 15:43:58 GMT
References: <3685@tank.uchicago.edu>
Distribution: usa
Organization: Common Sense Computing, McLean Va
Lines: 31

From article <3685@tank.uchicago.edu>, by barry@arthur.uchicago.edu:
> 
> A friend recently showed me a "technique" for making free phone
> calls from a payphone.

This might work on coin stations connected to ground-start only
service, but not on modern setups. Of course, it worked
fine in "War Games" for David Lightman, but then...

The older stations put the carbon transmitter directly across 
the phone pair and it modulated the current flowing through it; 
the paper clip gives you direct access to the phone pair. 

By shorting the carbon transmitter to ground, the CO
is fooled into thinking either proper payment has been
deposited or that an initial deposit has been made,
depending on the class of service and the total amount required. 

Modern arrangements require both the ground-start pulse to 
validate the inital deposit and the tone signalling used to 
indicate the total amount deposited, so in most places it
ain't as simple as you described. The joys of steppers...

You didn't mention whether or not these phones are 3-slotters
or 1-slotters. I am curious if there are any 3-slotters 
left in Chi-town.

-- 
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