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From: amb@cs.columbia.edu (Andrew Boardman)
Newsgroups: comp.dcom.telecom
Subject: Re: While Phone Rings, Charges May Begin
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Date: 10 Aug 89 15:05:52 GMT
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In article  tanner wrote:
>) ... green box ... tone to payphone
>Do payphones not use out-of-band signalling?  It would seem to invite
>abuse if they used in-band signalling, especially if someone were
>inclined to carry a recording of money being dropped into the thing.

They most certainly do use in-band signalling; in fact, such a recording
was floating around department where I used to work.  (For those that keep
track of such things, a circuit hardwired to produce the tones necessary
(coin deposit, not coin return) is referred to as a "red box".  (Construction
is trivial, but generally I prefer to pay for the service I get from AT&T.
I dread the day that I read "Coin calls from this telephone are carried by
the US Sprint PublicFON service."))

Andrew Boardman
amb@cs.columbia.edu
(but if you really have to, ab4@cunixc will work from bitnet)