      Bug Detection on Home phones
   (COURTESY OF DR JIMMY AND MR JIM)
 
   First of all to test for bugs, you need a VOM (Multimeter) the
higher the impedance the better (a Digital with FET circuitry or a
Vacuum Tube Volt Meter is the best).
 
   First disconnect the phone line(s) AT BOTH ENDS.  Undo the phone
instrument and hook it up to the entry point of the phone line from the
outside world (Ma Bell does not like you to cut her off completely.)
The scheme is to physically isolate your house, apartment, etc.,from
the outside world. But before you do this measure the line voltage (It
should be approximately 48 Volts).
 
  Now with the wires disconnected at both ends, set your resistance
scale to a high reading and measure the resistance of the phone line,
it should be very high on the order of million ohms or more, this is
the normal condition, since you are measuring the resistance of an open
circuit. If it is much less, say 50-100Kohms then you have a device on
the line that does not belong there, probably a parallel bug.
 
   Now twist the end of the disconnected wire and go to the other end
and measure the resistance of this. This resistance should be about one
ohm or two at the most in a big house with a lot of phones.  If it is
more, then you probably have a series bug.
 
   If in the first case, taking parallel measurements using a meter
(not LED/LCD) and you notice a 'kick' in the needle, you probably have
a line tap.
 
   Now if you also make a measurement with the wire end twisted
together and you notice the resistance reads about 1-2kohms, then you
may have a drop-out relay.  A drop-out relay is a relay that senses a
phone going off hook, and signals a tape recorder to start recording.
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