Anybody know what in the hell I'm talking about?

[hoffman-log.livejournal.com]

This might be the wrong community for it, but hell, we're all geeks. Somebody might know what I mean...

I'm doing research for a presentation/paper on TEMPEST. I have a good amount of data, but I want to make reference to a sort of device that can be placed on top of a phone line or networking cable that will pick up EMI fluctuations and can translate them into voice or data. Just to clarify, I'm not talking about a physical splicing of the line, but rather the interception of emanations from the cable (which is actually the fundamental basis for TEMPEST).

So, does anybody know what in the heck device I'm talking about? What's it called? Does it even exist, or am I just being hopeful?

_MaH