[mdlug] Curious - Phone Tapping Tech

[Michael Mol]

On Thu, Jun 21, 2012 at 2:36 PM, Michael Mol <mikemol at gmail.com> wrote:
> On Thu, Jun 21, 2012 at 2:25 PM, Robert Adkins II <radkins at impelind.com> wrote:

[snip]

>
>> None of which, I presume, is fundamentally easy to accomplish, setup,
>> configure and operate for the layman.
>
> A kit to take the output of a hall effect sensor and let you plug a
> speaker into it would probably cost around $25 in parts. Active
> components would be a hall effect sensor, an op-amp or two for
> amplification, and a power regulator. Mass-produced, it could probably
> be retailed for $20. It'd be shaped like a wand, with the sensor at
> the end, and your headphone jack in the handle.
>
> Operation would involve sticking a couple AA batteries in, plugging in
> your headphone and holding the device up against the phone cable. You
> could have sold it as a children's toy before everything went
> cordless.

Though, again, this would only work for a single-pair (or very low
pair-count) case. If you've got a 25-pair bundle, YMMV depending on
factors like pair positioning and how many other pairs are active. And
you probably want to use a former passive sonar operator for
understanding what you're hearing.

-- 
:wq