[mdlug] Curious - Phone Tapping Tech

[Aaron Kulkis]

Michael Mol wrote:
> On Thu, Jun 21, 2012 at 11:21 AM, Robert Adkins II <radkins at impelind.com> wrote:
>> I am curious to know if phone tapping technology has "caught up" with
>> Holywood. In terms of being able to take a band and wrap it around a bundle
>> of phone lines and call that a tapped line.
>>
>> I'm curious, because everything that I know regarding this technology
>> requires that each individual line be physically tapped/connected to in
>> order to obtain anything.
>>
>> I'm talking about Plain Old Telephone Service. Nothing fancy like IP based
>> or similar.
> 
> Oh, sure. When I was a kid, I could hear my parents' telephone
> conversations by picking up the second phone line; it's called
> crosstalk, and it's a form of accidental inductive coupling.
> 
> They've probably been making the accidental intentional since WWII.
> 

That's one pair PARALLEL to the other pair, and is an
entirely different scenario (wrapped AROUND the bundle, and
therefor, a plane perpendicular to the pair carrying the signal
to be detected).


> Doing the same thing with a *bundle* of cables would be a bit
> tricker...but you could probably do a decent job filtering crap out
> with enough signal processing. Filtering out DSL frequencies to start,
> then finding any frequency band groups that stop and start (as would
> happen with a human vocal conversation), and locking in on those.
> Eventually, you'd need to get a human involved to separate out
> overlapping conversations.
> 
> Though, no, I don't expect you could wrap around a bundle of cables
> and hone in on a specific copper pair.

You couldn't detect a signal even if it was only 1 copper pair.
Don't believe me?  Try it.

> It might be easier just to get
> the circuit on the copper pair physically closest to the one you're
> interested in. "Joe? Eavesdropper on line two."
>