hobbit@topaz.rutgers.edu (*Hobbit*) (11/01/88)
Some of the better tap detectors claim they can detect a tiny voltage drop when a high-impedance device is bridged across the line. Of course if it's already there, TFB. Professional tap detectors normally fire a bunch of test tones down the line and compare what they get back against what they think a "clean" line is. Having a TDR helps too... _H*
chip@vector.UUCP (Chip Rosenthal) (11/03/88)
In article <telecom-v08i0167m03@vector.UUCP>, hobbit@topaz.rutgers.edu (*Hobbit*) writes: > think a "clean" line is. Having a TDR helps too... I've TDR'ed my phone line on occasion just for kicks. I have to wonder whether it is really possible to spot anything but a bug that is grossly mismatched to the phone line, as the average line is so junky that you would be astounded. I can spot things like the transition from internal wiring -> interface, maybe phone poll wiring, but not much else. A bug that is capacitively coupled into the line would be most difficult to see on the TDR (especially if placed near the interface); it would also slip by the DC level detector type "tap spotters". Rick Spanbauer SUNY/Stony Brook