Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!bellcore!texbell!vector!telecom-gateway From: zygot!john@apple.com (John Higdon) Newsgroups: comp.dcom.telecom Subject: Re: While Phone Rings, Charges May Begin Message-ID:Date: 10 Aug 89 17:41:26 GMT Sender: news@vector.Dallas.TX.US Organization: ATI Wares Team Lines: 26 Approved: telecom-request@vector.dallas.tx.us X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@vector.dallas.tx.us X-TELECOM-Digest: volume 9, issue 289, message 6 of 8 In article , tanner@ki4pv.uucp (Dr. T. Andrews) writes: > ) ... 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. The insertion of money causes in-band signaling. It makes a little beep that is muted so that you don't hear it. One beep per five cents. This totals up on a display that the operator has in front of her (or on the automatic coin collection equipment.) It is a trivial matter to imitate these beeps with a device called a "red box". However, the first coin must be real, since the phone signals via DC loop that there is indeed at least one coin in the hopper (the first coin trips a flapper in the chute which is reset each time the hopper dumps to either the coin box or the return). If this signal is not present, they know you are pulling something. Pac*Bell has a few fraud prevention techniques to prevent this. One of them is to periodically and without warning dump the hopper into the coin box so that a new real coin will have to be inserted. Any dicrepancies and you better watch out. There are others which I'll keep to myself for now. -- John Higdon | P. O. Box 7648 | +1 408 723 1395 john@zygot.uucp | San Jose, CA 95150 | M o o !