17
Using the Toner
To turn on the Line Verification function:
1
Press M.
2
Press C to put the flashing cursor next to TDR,
then press
M.
3
Press D to put the flashing cursor next to Line
Verif
, then press M to select Line Verif.
4
Press R or L to select On or Off.
5
To save your selection before you exit or go back
to the main menu, press
M. The display shows
Saved.
To go back to the previous menu, press Q. Or,
press
C or D until Back shows, then press
M.
VOP
To get the most accurate measurements of the length
of a cable or the distance to a fault, set the velocity of
propagation to the correct value for the cable.
See"Velocity of Propagation (VOP)" on page 22.
Using the TDR on Multi-Wire Cables
In a multi-wire cable, such as 4 wire telephone cable, 8
wire CAT-5 cable, 12-2 with ground ac wire, or several
THHN wires inside a conduit, a short can exist between
any of the conductors, including a shield or the
conduit. To detect the short, you must connect the test
set to the wires that are shorted. This means that to
fully test a multi-wire cable, you must test every wire
against every other wire including the shields and
conduits.
While a quick way to test many conductors against
conduit or shield length is to connect all the conductors
to one clip lead and the shield to the other lead, this
will reduce the impedance of the cable, and
measurements may fall below the test set’s range. It is
more reliable to test the wires individually.
If the TDR Shows Unusual or Unstable
Length Measurements
Devices connected to the line can make the TDR show
unusual or unstable measurements. Such devices
include bridge taps, inactive telephone equipment, and
transformers.
Using the Toner
The toner helps you identify wire pairs and find cables
in bundles, at patch panels, or behind walls. The toner
puts a signal on a wire pair, then you use an optional,
inductive probe to find the signal. The toner has five
different tones.
The SmartTone function helps you make sure you
correctly identify a wire pair. When you put a short on
the correct pair, the tone changes.
Notes
The toner does not operate on wire pairs that
have DC or AC voltage or on pairs that are
terminated.
The toner can cause interference on adjacent
wire pairs. To minimize problems with services
on those pairs, complete your work with the
toner quickly.
The toner uses a lot of battery power. To
preserve the life of the battery, turn off the
toner when you do not use it.
Finding a Cable
To find a cable:
1
Turn on the test set.
2
Connect the test set to one end of the cable (see
Figure 2).
-continued-
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