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: <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