Newsgroups: sci.electronics
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Trace-Back on phones
Message-ID: <1989Dec28.233023.12561@utzoo.uucp>
Organization: U of Toronto Zoology
References: <SAAF.89Sep12215929@joker.optics.rochester.edu> <89256.111005BHB3@PSUVM.BITNET> <4344@aplcen.apl.jhu.edu> <6693@lindy.Stanford.EDU>
Date: Thu, 28 Dec 89 23:30:23 GMT

In article <6693@lindy.Stanford.EDU> sorka@ucscb.UCSC.EDU (Alan Waterman) writes:
>>The question I have is whether or not anyone knows anything about whether or
>>not one can run a traceback on a phonecall.  A friend of mine says that the
>>phone company is now transmitting a "header" with the call that, if one knows
>>the format, could decode it at display the calling number...
>
>I would also like to get info on this subject.

I replied by mail to the original, since that's what was requested, but I
suppose it's worth a brief posting...

A service like this is available in some areas.  Only some phone switches
support it.  Generally it costs money to get it; it is *not* supplied
free to everyone.  (The phone companies are under great pressure to keep
the cost of basic telephone service low, which means charging all the
traffic will bear for everything else.  Services like call forwarding,
when available at all, generally cost the phone company nothing to provide,
and tone-dialing service is actually *cheaper* for them than rotary
dialing... but charging extra for such "luxury" services provides money
that can be used to subsidize basic service.)  Claims that it's being done
everywhere for free appear regularly, but they are myths.  If you are
interested in such a service, ask your phone company whether it's available
and how much it costs.
-- 
1972: Saturn V #15 flight-ready|     Henry Spencer at U of Toronto Zoology
1989: birds nesting in engines | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
